ACTIVE AND PASSIVE CONTROL OF A REVOLUTE-PRISMATIC FLEXIBLE COMPOSITE-MATERIAL ROBOT ARM

The focus of this paper is on reducing the positional inaccuracies of a flexible, revolute-prismatic robotic manipulator due to the undesire d static and dynamic deflections. A strategy combining active and pass ive compensations is employed. Active control is performed by using a controller which compensates for both the rigid body and flexible moti ons. Passive compensation is by fabricating the robotic manipulator fr om advanced composite materials. This aids the controller in reducing the undesired static and dynamic deflections by increasing the arm's s tiffness-to-weight ratio. The effects of large displacements, shear de formation and rotary inertia are included in the dynamic model of the robot arm. The displacement finite element along with Gear's method is adopted to approximate the solution. Comparisons are made of the perf ormance of the robot arms constructed from conventional metallic mater ials and advanced composites. The positional accuracy of the end effec tor and the energy consumption of the actuators are enhanced by the si multaneous use of the nonlinear control and fabrication of the robot a rm from advanced composites.