How Does a Robot Know Where to Step? Measuring the Hardness and Roughness of Surfaces

This paper presents an overview of ongoing research on surface exploration at the GRASP Lab. We are investigating the necessary components and modules that must be embedded into a robot for it to have the exploratory capabilities required to recover mechanical properties from a surface given minimal a priori information. Eventually, this information will be used to enable a robot stand and walk stably in an environment that is unknown and unconstrained. The laboratory setup involves a compliant wrist with six degrees of freedom, mounted on a robot arm, and a prototype foot mounted on the wrist. We have successfully designed and implemented exploratory procedures (ep\u27s) to recover penetrability, material hardness and frictional characteristics by exploring the surface

Robotic Exploration of Surfaces to Measure Mechanical Properties

This paper presents an overview of ongoing research on surface exploration at the GRASP Lab. We are investigating the necessary components and modules that must be embedded into a robot for it to have the exploratory capabilities required to recover mechanical properties from a surface, given minimal a priori information. Eventually, this information will be used to enable a robot to stand and walk stably on a surface that is unknown and unconstrained. A robot in the agricultural environment will specially benefit from such capabilities since it will need to step and walk on soils with variable properties. The paper proposes a framework for the recovery of the attributes of interest, and describes the laboratory setup designed to test the framework. The design and implementation of exploratory procedures (ep\u27s) to recover penetrability, material hardness and surface roughness by exploring the surface is also described

Active Exploration of Surfaces for Legged Locomotion of Robots

This paper presents some results of an ongoing research project in the GRASP Lab in the area of active exploration and perception for the legged locomotion of robots. We propose an active perceptual scheme that is based on the ability of the robot to extract material properties from a surface during locomotion. This ability is provided to the robotic system through a compliant sensing device which is used to monitor the response of the surface when exploratory procedures are executed during the stepping and walking motions of the leg. Such a system will actively perceive changes in the surfaces properties and prevent the robot from slipping, falling, or sinking during locomotion. The paper describes the proposed perceptual scheme, the system set-up, and the implementation of the exploratory procedures

Robotic Exploration of Surfaces With a Compliant Wrist Sensor

This paper presents some results of an ongoing research project to investigate the components and modules that are necessary to equip a robot with exploratory capabilities. Of particular interest is the recovery of certain material properties from a surface, given minimal a priori information, with the intent to use this information to enable a robot to stand and walk stably on a surface that is unknown and unconstrained. To this end, exploratory procedures (ep\u27s) have been designed and implemented to recover penetrability, material hardness and surface roughness by exploring the surface using a compliant wrist sensor. A six degree-of-freedom compliant wrist sensor, which combines passive compliance and active sensing, has been developed to provide the necessary flexibility for force and contact control, as well as to provide accurate position control. This paper describes the compliant wrist and sensing mechanism design along with a hybrid control algorithm that utilizes the sensed information from the wrist to adjust the apparent stiffness of the end-effector as desired