herman herman - Academia.edu (original) (raw)
Papers by herman herman
Journal of Materials Science, 1997
The porous phase of plasma-sprayed alumina was characterized using mercury intrusion porosimetry,... more The porous phase of plasma-sprayed alumina was characterized using mercury intrusion porosimetry, water immersion methods, and small-angle neutron scattering. A comparison of the results shows that the intrusion techniques did not yield a full porous phase characterization. It has been found that while the amount of closed porosity was 1.4%(±0.5%) of the sample volume, this volume accounted for only 60% of the total internal surface area. The smallest void diameter was found to be 10 nm.
Mobile manipulators currently deployed for explosive ordinance disposal are typically controlled ... more Mobile manipulators currently deployed for explosive ordinance disposal are typically controlled via crude forms of teleoperation.Manipulator joints are actuated individually in joint space, making precise motions in state space difficult. Scene understanding is limited, as monocular cameras provide little (if any) depth information. Furthermore, the operator must manually coordinate the manipulator articulation with the positioning of the mobile base. These limitations place greater demands on the operator, decrease task efficiency and can increase exposure in dangerous environments. In this paper, we demonstrate several enabling technologies for interacting with and operating mobile manipulators, including a “click-and-grab” interface for coordinated motion and manipulation. This includes coordinated joint movement for end-effector position control, a flash LADAR to provide depth information, and automatic trajectory generation to autonomously position the mobile base and manipulator.
Using surface and subsurface sensing, we have developed a perception system for autonomous retrie... more Using surface and subsurface sensing, we have developed a perception system for autonomous retrieval of buried objects. The subsurface sensing system uses Ground Penetrating Radar (GPR) to locate buried objects. A 2D laser rangefinder system generates an elevation map, and using this map a robotic arm positions the GPR antenna. This setup allows us to automate the GPR data collection. An image processing algorithm is used to locate the object of interest in the GPR data. After it is located, we use sense and dig cycle to retrieve the object.
The most challenging technical problems facing successful autonomous UGV operation in off-road en... more The most challenging technical problems facing successful autonomous UGV operation in off-road environments are reliable sensing and perception. In this paper, we describe our progress over the last year toward solving these problems in Phase II of DARPA's PerceptOR program. We have developed a perception system that combines laser, camera, and proprioceptive sensing elements on both ground and air platforms to detect and avoid obstacles in natural terrain environments. The perception system has been rigorously tested in a variety of environments and has improved over time as problems have been identified and systematically solved. The paper describes the perception system and the autonomous vehicles, presents results from some experiments, and summarizes the current capabilities and limitations.
This paper presents a vehicle for autonomous off-road navigation built in the framework of DARPA'... more This paper presents a vehicle for autonomous off-road navigation built in the framework of DARPA's PerceptOR program. Special emphasis is given to the perception system. A set of three stereo camera pairs provide color and 3D data in a wide field of view (greater 100 degree) at high resolution (2160 by 480 pixel) and high frame rates (5 Hz). This is made possible by integrating a powerful image processing hardware called Acadia. These high data rates require efficient sensor fusion, terrain reconstruction and path planning algorithms. The paper quantifies sensor performance and shows examples of successful obstacle avoidance.
Underground coal mining is an industry well suited for robotic automation. Human operators are se... more Underground coal mining is an industry well suited for robotic automation. Human operators are severely hampered in dark, dusty, and cramped mines, and productivity suffers. Even a slight improvement in productivity can amount to thousands of dollars of additional revenue per machine per day. Automation to date has relied on infrastructure to guide the equipment. The industry finds this approach unsuitable, and it has not taken root. Our approach uses machine-mounted video cameras to guide the equipment. It utilizes natural infrastructure and equipment commonly used in mines. We have demonstrated that our approach meets the requirements for cutting straight entries and mining the proper amount of coal per cycle. The technology is rapidly approaching beta form and will be deployed in several mines in the coming months. Figure 1: Room and Pillar Mining. Top shows continuous miner, shuttle cars, roof bolter, and conveyor. Bottom shows continuous miner and shuttle cars.
Flash ladar is a new class of range imaging sensors. Unlike traditional ladar devices that scan a... more Flash ladar is a new class of range imaging sensors. Unlike traditional ladar devices that scan a collimated laser beam over the scene, flash ladar illuminates the entire scene with diffuse laser light. Recently, several companies have begun offering demonstration flash ladar units commercially. In this work, we seek to characterize the performance of two such devices, examining the effects of target range, reflectance and angle of incidence, as well as mixed pixel effects.
Autonomous Robots, 2002
Tractors are the workhorses of the modern farm. By automating these machines, we can increase the... more Tractors are the workhorses of the modern farm. By automating these machines, we can increase the productivity, improve safety, and reduce costs for many agricultural operations. Many researchers have tested computer-controlled machines for farming, but few have investigated the larger issues such as how humans can supervise machines and work amongst them. In this paper, we present a system for tractor automation. A human programs a task by driving the relevant routes. The task is divided into subtasks and assigned to a fleet of tractors that drive portions of the routes. Each tractor uses on-board sensors to detect people, animals, and other vehicles in the path of the machine, stopping for such obstacles until it receives advice from a supervisor over a wireless link. A first version of the system was implemented on a single tractor. Several features of the system were validated, including accurate path tracking, the detection of obstacles based on both geometric and non-geometric properties, and self-monitoring to determine when human intervention is required. Additionally, the complete system was tested in a Florida orange grove, where it autonomously drove seven kilometers.
The DARPA PerceptOR program implements a rigorous evaluative test program which fosters the devel... more The DARPA PerceptOR program implements a rigorous evaluative test program which fosters the development of field relevant outdoor mobile robots. Autonomous ground vehicles are deployed on diverse test courses throughout the USA and quantitatively evaluated on such factors as autonomy level, waypoint acquisition, failure rate, speed, and communications bandwidth. Our efforts over the three year program have produced new approaches in planning, perception, localization, and control which have been driven by the quest for reliable operation in challenging environments. This paper focuses on some of the most unique aspects of the systems developed by the CMU PerceptOR team and the most immediate challenges that remain to be addressed.
International Journal of Robotic Research, 2006
The DARPA PerceptOR program has implemented a rigorous evaluative test program which fosters the ... more The DARPA PerceptOR program has implemented a rigorous evaluative test program which fosters the development of field relevant outdoor mobile robots. Autonomous ground vehicles were deployed on diverse test courses throughout the USA and quantitatively evaluated on such factors as autonomy level, waypoint acquisition, failure rate, speed, and communications bandwidth. Our efforts over the three year program have produced new approaches in planning, perception, localization, and control which have been driven by the quest for reliable operation in challenging environments. This paper focuses on some of the most unique aspects of the systems developed by the CMU PerceptOR team, the lessons learned during the effort, and the most immediate challenges that remain to be addressed.
Autonomous Robots, 2002
Tractors are the workhorses of the modern farm. By automating these machines, we can increase the... more Tractors are the workhorses of the modern farm. By automating these machines, we can increase the productivity, improve safety, and reduce costs for many agricultural operations. Many researchers have tested computer-controlled machines for farming, but few have investigated the larger issues such as how humans can supervise machines and work amongst them. In this paper, we present a system for tractor automation. A human programs a task by driving the relevant routes. The task is divided into subtasks and assigned to a fleet of tractors that drive portions of the routes. Each tractor uses on-board sensors to detect people, animals, and other vehicles in the path of the machine, stopping for such obstacles until it receives advice from a supervisor over a wireless link. A first version of the system was implemented on a single tractor. Several features of the system were validated, including accurate path tracking, the detection of obstacles based on both geometric and non-geometric properties, and self-monitoring to determine when human intervention is required. Additionally, the complete system was tested in a Florida orange grove, where it autonomously drove seven kilometers.
Journal of Materials Science, 1997
The porous phase of plasma-sprayed alumina was characterized using mercury intrusion porosimetry,... more The porous phase of plasma-sprayed alumina was characterized using mercury intrusion porosimetry, water immersion methods, and small-angle neutron scattering. A comparison of the results shows that the intrusion techniques did not yield a full porous phase characterization. It has been found that while the amount of closed porosity was 1.4%(±0.5%) of the sample volume, this volume accounted for only 60% of the total internal surface area. The smallest void diameter was found to be 10 nm.
Mobile manipulators currently deployed for explosive ordinance disposal are typically controlled ... more Mobile manipulators currently deployed for explosive ordinance disposal are typically controlled via crude forms of teleoperation.Manipulator joints are actuated individually in joint space, making precise motions in state space difficult. Scene understanding is limited, as monocular cameras provide little (if any) depth information. Furthermore, the operator must manually coordinate the manipulator articulation with the positioning of the mobile base. These limitations place greater demands on the operator, decrease task efficiency and can increase exposure in dangerous environments. In this paper, we demonstrate several enabling technologies for interacting with and operating mobile manipulators, including a “click-and-grab” interface for coordinated motion and manipulation. This includes coordinated joint movement for end-effector position control, a flash LADAR to provide depth information, and automatic trajectory generation to autonomously position the mobile base and manipulator.
Using surface and subsurface sensing, we have developed a perception system for autonomous retrie... more Using surface and subsurface sensing, we have developed a perception system for autonomous retrieval of buried objects. The subsurface sensing system uses Ground Penetrating Radar (GPR) to locate buried objects. A 2D laser rangefinder system generates an elevation map, and using this map a robotic arm positions the GPR antenna. This setup allows us to automate the GPR data collection. An image processing algorithm is used to locate the object of interest in the GPR data. After it is located, we use sense and dig cycle to retrieve the object.
The most challenging technical problems facing successful autonomous UGV operation in off-road en... more The most challenging technical problems facing successful autonomous UGV operation in off-road environments are reliable sensing and perception. In this paper, we describe our progress over the last year toward solving these problems in Phase II of DARPA's PerceptOR program. We have developed a perception system that combines laser, camera, and proprioceptive sensing elements on both ground and air platforms to detect and avoid obstacles in natural terrain environments. The perception system has been rigorously tested in a variety of environments and has improved over time as problems have been identified and systematically solved. The paper describes the perception system and the autonomous vehicles, presents results from some experiments, and summarizes the current capabilities and limitations.
This paper presents a vehicle for autonomous off-road navigation built in the framework of DARPA'... more This paper presents a vehicle for autonomous off-road navigation built in the framework of DARPA's PerceptOR program. Special emphasis is given to the perception system. A set of three stereo camera pairs provide color and 3D data in a wide field of view (greater 100 degree) at high resolution (2160 by 480 pixel) and high frame rates (5 Hz). This is made possible by integrating a powerful image processing hardware called Acadia. These high data rates require efficient sensor fusion, terrain reconstruction and path planning algorithms. The paper quantifies sensor performance and shows examples of successful obstacle avoidance.
Underground coal mining is an industry well suited for robotic automation. Human operators are se... more Underground coal mining is an industry well suited for robotic automation. Human operators are severely hampered in dark, dusty, and cramped mines, and productivity suffers. Even a slight improvement in productivity can amount to thousands of dollars of additional revenue per machine per day. Automation to date has relied on infrastructure to guide the equipment. The industry finds this approach unsuitable, and it has not taken root. Our approach uses machine-mounted video cameras to guide the equipment. It utilizes natural infrastructure and equipment commonly used in mines. We have demonstrated that our approach meets the requirements for cutting straight entries and mining the proper amount of coal per cycle. The technology is rapidly approaching beta form and will be deployed in several mines in the coming months. Figure 1: Room and Pillar Mining. Top shows continuous miner, shuttle cars, roof bolter, and conveyor. Bottom shows continuous miner and shuttle cars.
Flash ladar is a new class of range imaging sensors. Unlike traditional ladar devices that scan a... more Flash ladar is a new class of range imaging sensors. Unlike traditional ladar devices that scan a collimated laser beam over the scene, flash ladar illuminates the entire scene with diffuse laser light. Recently, several companies have begun offering demonstration flash ladar units commercially. In this work, we seek to characterize the performance of two such devices, examining the effects of target range, reflectance and angle of incidence, as well as mixed pixel effects.
Autonomous Robots, 2002
Tractors are the workhorses of the modern farm. By automating these machines, we can increase the... more Tractors are the workhorses of the modern farm. By automating these machines, we can increase the productivity, improve safety, and reduce costs for many agricultural operations. Many researchers have tested computer-controlled machines for farming, but few have investigated the larger issues such as how humans can supervise machines and work amongst them. In this paper, we present a system for tractor automation. A human programs a task by driving the relevant routes. The task is divided into subtasks and assigned to a fleet of tractors that drive portions of the routes. Each tractor uses on-board sensors to detect people, animals, and other vehicles in the path of the machine, stopping for such obstacles until it receives advice from a supervisor over a wireless link. A first version of the system was implemented on a single tractor. Several features of the system were validated, including accurate path tracking, the detection of obstacles based on both geometric and non-geometric properties, and self-monitoring to determine when human intervention is required. Additionally, the complete system was tested in a Florida orange grove, where it autonomously drove seven kilometers.
The DARPA PerceptOR program implements a rigorous evaluative test program which fosters the devel... more The DARPA PerceptOR program implements a rigorous evaluative test program which fosters the development of field relevant outdoor mobile robots. Autonomous ground vehicles are deployed on diverse test courses throughout the USA and quantitatively evaluated on such factors as autonomy level, waypoint acquisition, failure rate, speed, and communications bandwidth. Our efforts over the three year program have produced new approaches in planning, perception, localization, and control which have been driven by the quest for reliable operation in challenging environments. This paper focuses on some of the most unique aspects of the systems developed by the CMU PerceptOR team and the most immediate challenges that remain to be addressed.
Journal of Materials Science, 1997
The porous phase of plasma-sprayed alumina was characterized using mercury intrusion porosimetry,... more The porous phase of plasma-sprayed alumina was characterized using mercury intrusion porosimetry, water immersion methods, and small-angle neutron scattering. A comparison of the results shows that the intrusion techniques did not yield a full porous phase characterization. It has been found that while the amount of closed porosity was 1.4%(±0.5%) of the sample volume, this volume accounted for only 60% of the total internal surface area. The smallest void diameter was found to be 10 nm.
Mobile manipulators currently deployed for explosive ordinance disposal are typically controlled ... more Mobile manipulators currently deployed for explosive ordinance disposal are typically controlled via crude forms of teleoperation.Manipulator joints are actuated individually in joint space, making precise motions in state space difficult. Scene understanding is limited, as monocular cameras provide little (if any) depth information. Furthermore, the operator must manually coordinate the manipulator articulation with the positioning of the mobile base. These limitations place greater demands on the operator, decrease task efficiency and can increase exposure in dangerous environments. In this paper, we demonstrate several enabling technologies for interacting with and operating mobile manipulators, including a “click-and-grab” interface for coordinated motion and manipulation. This includes coordinated joint movement for end-effector position control, a flash LADAR to provide depth information, and automatic trajectory generation to autonomously position the mobile base and manipulator.
Using surface and subsurface sensing, we have developed a perception system for autonomous retrie... more Using surface and subsurface sensing, we have developed a perception system for autonomous retrieval of buried objects. The subsurface sensing system uses Ground Penetrating Radar (GPR) to locate buried objects. A 2D laser rangefinder system generates an elevation map, and using this map a robotic arm positions the GPR antenna. This setup allows us to automate the GPR data collection. An image processing algorithm is used to locate the object of interest in the GPR data. After it is located, we use sense and dig cycle to retrieve the object.
The most challenging technical problems facing successful autonomous UGV operation in off-road en... more The most challenging technical problems facing successful autonomous UGV operation in off-road environments are reliable sensing and perception. In this paper, we describe our progress over the last year toward solving these problems in Phase II of DARPA's PerceptOR program. We have developed a perception system that combines laser, camera, and proprioceptive sensing elements on both ground and air platforms to detect and avoid obstacles in natural terrain environments. The perception system has been rigorously tested in a variety of environments and has improved over time as problems have been identified and systematically solved. The paper describes the perception system and the autonomous vehicles, presents results from some experiments, and summarizes the current capabilities and limitations.
This paper presents a vehicle for autonomous off-road navigation built in the framework of DARPA'... more This paper presents a vehicle for autonomous off-road navigation built in the framework of DARPA's PerceptOR program. Special emphasis is given to the perception system. A set of three stereo camera pairs provide color and 3D data in a wide field of view (greater 100 degree) at high resolution (2160 by 480 pixel) and high frame rates (5 Hz). This is made possible by integrating a powerful image processing hardware called Acadia. These high data rates require efficient sensor fusion, terrain reconstruction and path planning algorithms. The paper quantifies sensor performance and shows examples of successful obstacle avoidance.
Underground coal mining is an industry well suited for robotic automation. Human operators are se... more Underground coal mining is an industry well suited for robotic automation. Human operators are severely hampered in dark, dusty, and cramped mines, and productivity suffers. Even a slight improvement in productivity can amount to thousands of dollars of additional revenue per machine per day. Automation to date has relied on infrastructure to guide the equipment. The industry finds this approach unsuitable, and it has not taken root. Our approach uses machine-mounted video cameras to guide the equipment. It utilizes natural infrastructure and equipment commonly used in mines. We have demonstrated that our approach meets the requirements for cutting straight entries and mining the proper amount of coal per cycle. The technology is rapidly approaching beta form and will be deployed in several mines in the coming months. Figure 1: Room and Pillar Mining. Top shows continuous miner, shuttle cars, roof bolter, and conveyor. Bottom shows continuous miner and shuttle cars.
Flash ladar is a new class of range imaging sensors. Unlike traditional ladar devices that scan a... more Flash ladar is a new class of range imaging sensors. Unlike traditional ladar devices that scan a collimated laser beam over the scene, flash ladar illuminates the entire scene with diffuse laser light. Recently, several companies have begun offering demonstration flash ladar units commercially. In this work, we seek to characterize the performance of two such devices, examining the effects of target range, reflectance and angle of incidence, as well as mixed pixel effects.
Autonomous Robots, 2002
Tractors are the workhorses of the modern farm. By automating these machines, we can increase the... more Tractors are the workhorses of the modern farm. By automating these machines, we can increase the productivity, improve safety, and reduce costs for many agricultural operations. Many researchers have tested computer-controlled machines for farming, but few have investigated the larger issues such as how humans can supervise machines and work amongst them. In this paper, we present a system for tractor automation. A human programs a task by driving the relevant routes. The task is divided into subtasks and assigned to a fleet of tractors that drive portions of the routes. Each tractor uses on-board sensors to detect people, animals, and other vehicles in the path of the machine, stopping for such obstacles until it receives advice from a supervisor over a wireless link. A first version of the system was implemented on a single tractor. Several features of the system were validated, including accurate path tracking, the detection of obstacles based on both geometric and non-geometric properties, and self-monitoring to determine when human intervention is required. Additionally, the complete system was tested in a Florida orange grove, where it autonomously drove seven kilometers.
The DARPA PerceptOR program implements a rigorous evaluative test program which fosters the devel... more The DARPA PerceptOR program implements a rigorous evaluative test program which fosters the development of field relevant outdoor mobile robots. Autonomous ground vehicles are deployed on diverse test courses throughout the USA and quantitatively evaluated on such factors as autonomy level, waypoint acquisition, failure rate, speed, and communications bandwidth. Our efforts over the three year program have produced new approaches in planning, perception, localization, and control which have been driven by the quest for reliable operation in challenging environments. This paper focuses on some of the most unique aspects of the systems developed by the CMU PerceptOR team and the most immediate challenges that remain to be addressed.
International Journal of Robotic Research, 2006
The DARPA PerceptOR program has implemented a rigorous evaluative test program which fosters the ... more The DARPA PerceptOR program has implemented a rigorous evaluative test program which fosters the development of field relevant outdoor mobile robots. Autonomous ground vehicles were deployed on diverse test courses throughout the USA and quantitatively evaluated on such factors as autonomy level, waypoint acquisition, failure rate, speed, and communications bandwidth. Our efforts over the three year program have produced new approaches in planning, perception, localization, and control which have been driven by the quest for reliable operation in challenging environments. This paper focuses on some of the most unique aspects of the systems developed by the CMU PerceptOR team, the lessons learned during the effort, and the most immediate challenges that remain to be addressed.
Autonomous Robots, 2002
Tractors are the workhorses of the modern farm. By automating these machines, we can increase the... more Tractors are the workhorses of the modern farm. By automating these machines, we can increase the productivity, improve safety, and reduce costs for many agricultural operations. Many researchers have tested computer-controlled machines for farming, but few have investigated the larger issues such as how humans can supervise machines and work amongst them. In this paper, we present a system for tractor automation. A human programs a task by driving the relevant routes. The task is divided into subtasks and assigned to a fleet of tractors that drive portions of the routes. Each tractor uses on-board sensors to detect people, animals, and other vehicles in the path of the machine, stopping for such obstacles until it receives advice from a supervisor over a wireless link. A first version of the system was implemented on a single tractor. Several features of the system were validated, including accurate path tracking, the detection of obstacles based on both geometric and non-geometric properties, and self-monitoring to determine when human intervention is required. Additionally, the complete system was tested in a Florida orange grove, where it autonomously drove seven kilometers.
Journal of Materials Science, 1997
The porous phase of plasma-sprayed alumina was characterized using mercury intrusion porosimetry,... more The porous phase of plasma-sprayed alumina was characterized using mercury intrusion porosimetry, water immersion methods, and small-angle neutron scattering. A comparison of the results shows that the intrusion techniques did not yield a full porous phase characterization. It has been found that while the amount of closed porosity was 1.4%(±0.5%) of the sample volume, this volume accounted for only 60% of the total internal surface area. The smallest void diameter was found to be 10 nm.
Mobile manipulators currently deployed for explosive ordinance disposal are typically controlled ... more Mobile manipulators currently deployed for explosive ordinance disposal are typically controlled via crude forms of teleoperation.Manipulator joints are actuated individually in joint space, making precise motions in state space difficult. Scene understanding is limited, as monocular cameras provide little (if any) depth information. Furthermore, the operator must manually coordinate the manipulator articulation with the positioning of the mobile base. These limitations place greater demands on the operator, decrease task efficiency and can increase exposure in dangerous environments. In this paper, we demonstrate several enabling technologies for interacting with and operating mobile manipulators, including a “click-and-grab” interface for coordinated motion and manipulation. This includes coordinated joint movement for end-effector position control, a flash LADAR to provide depth information, and automatic trajectory generation to autonomously position the mobile base and manipulator.
Using surface and subsurface sensing, we have developed a perception system for autonomous retrie... more Using surface and subsurface sensing, we have developed a perception system for autonomous retrieval of buried objects. The subsurface sensing system uses Ground Penetrating Radar (GPR) to locate buried objects. A 2D laser rangefinder system generates an elevation map, and using this map a robotic arm positions the GPR antenna. This setup allows us to automate the GPR data collection. An image processing algorithm is used to locate the object of interest in the GPR data. After it is located, we use sense and dig cycle to retrieve the object.
The most challenging technical problems facing successful autonomous UGV operation in off-road en... more The most challenging technical problems facing successful autonomous UGV operation in off-road environments are reliable sensing and perception. In this paper, we describe our progress over the last year toward solving these problems in Phase II of DARPA's PerceptOR program. We have developed a perception system that combines laser, camera, and proprioceptive sensing elements on both ground and air platforms to detect and avoid obstacles in natural terrain environments. The perception system has been rigorously tested in a variety of environments and has improved over time as problems have been identified and systematically solved. The paper describes the perception system and the autonomous vehicles, presents results from some experiments, and summarizes the current capabilities and limitations.
This paper presents a vehicle for autonomous off-road navigation built in the framework of DARPA'... more This paper presents a vehicle for autonomous off-road navigation built in the framework of DARPA's PerceptOR program. Special emphasis is given to the perception system. A set of three stereo camera pairs provide color and 3D data in a wide field of view (greater 100 degree) at high resolution (2160 by 480 pixel) and high frame rates (5 Hz). This is made possible by integrating a powerful image processing hardware called Acadia. These high data rates require efficient sensor fusion, terrain reconstruction and path planning algorithms. The paper quantifies sensor performance and shows examples of successful obstacle avoidance.
Underground coal mining is an industry well suited for robotic automation. Human operators are se... more Underground coal mining is an industry well suited for robotic automation. Human operators are severely hampered in dark, dusty, and cramped mines, and productivity suffers. Even a slight improvement in productivity can amount to thousands of dollars of additional revenue per machine per day. Automation to date has relied on infrastructure to guide the equipment. The industry finds this approach unsuitable, and it has not taken root. Our approach uses machine-mounted video cameras to guide the equipment. It utilizes natural infrastructure and equipment commonly used in mines. We have demonstrated that our approach meets the requirements for cutting straight entries and mining the proper amount of coal per cycle. The technology is rapidly approaching beta form and will be deployed in several mines in the coming months. Figure 1: Room and Pillar Mining. Top shows continuous miner, shuttle cars, roof bolter, and conveyor. Bottom shows continuous miner and shuttle cars.
Flash ladar is a new class of range imaging sensors. Unlike traditional ladar devices that scan a... more Flash ladar is a new class of range imaging sensors. Unlike traditional ladar devices that scan a collimated laser beam over the scene, flash ladar illuminates the entire scene with diffuse laser light. Recently, several companies have begun offering demonstration flash ladar units commercially. In this work, we seek to characterize the performance of two such devices, examining the effects of target range, reflectance and angle of incidence, as well as mixed pixel effects.
Autonomous Robots, 2002
Tractors are the workhorses of the modern farm. By automating these machines, we can increase the... more Tractors are the workhorses of the modern farm. By automating these machines, we can increase the productivity, improve safety, and reduce costs for many agricultural operations. Many researchers have tested computer-controlled machines for farming, but few have investigated the larger issues such as how humans can supervise machines and work amongst them. In this paper, we present a system for tractor automation. A human programs a task by driving the relevant routes. The task is divided into subtasks and assigned to a fleet of tractors that drive portions of the routes. Each tractor uses on-board sensors to detect people, animals, and other vehicles in the path of the machine, stopping for such obstacles until it receives advice from a supervisor over a wireless link. A first version of the system was implemented on a single tractor. Several features of the system were validated, including accurate path tracking, the detection of obstacles based on both geometric and non-geometric properties, and self-monitoring to determine when human intervention is required. Additionally, the complete system was tested in a Florida orange grove, where it autonomously drove seven kilometers.
The DARPA PerceptOR program implements a rigorous evaluative test program which fosters the devel... more The DARPA PerceptOR program implements a rigorous evaluative test program which fosters the development of field relevant outdoor mobile robots. Autonomous ground vehicles are deployed on diverse test courses throughout the USA and quantitatively evaluated on such factors as autonomy level, waypoint acquisition, failure rate, speed, and communications bandwidth. Our efforts over the three year program have produced new approaches in planning, perception, localization, and control which have been driven by the quest for reliable operation in challenging environments. This paper focuses on some of the most unique aspects of the systems developed by the CMU PerceptOR team and the most immediate challenges that remain to be addressed.