In this thesis, methods for parameter identification and for the control of flexible joint robots are developed. These methods are implemented on the DLR light-weight robots and are extensively tested during daily use. The flexible joint model applies to both industrial robots operating at high velocity and to ultra light-weight robots, such as used for service or space applications. Starting from a joint state feedback controller with constant parameters and compensation of the rigid robot dynamics, controllers of increasing complexity are proposed and tested. The methods include a state feedback controller with variable parameters and a passivity based controller with energy shaping. A main focus of the thesis is on the stability proof for the controllers, with consideration of the complete nonlinear dynamics of the flexible joint robots. It turns out that the state feedback controller with gravity compensation represents a simple and robust structure which provides an effective damping of the vibrations caused by elasticity and for which a Lyapunov stability proof can be derived. The state vector of the system contains the measured motor positions and joint torques, as well as the numerical derivatives of these signals. Consequently, the controller structure can be parameterized as a position, a torque or an impedance controller. Based on these joint interfaces, various solutions for a programmable Cartesian compliance are implemented and tested. Finally a new method, the global impedance controller with local stiffness control, is proposed.
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In this thesis, methods for parameter identification and for the control of flexible joint robots are developed. These methods are implemented on the DLR light-weight robots and are extensively tested during daily use. The flexible joint model applies to both industrial robots operating at high velocity and to ultra light-weight robots, such as used for service or space applications. Starting from a joint state feedback controller with constant parameters and compensation of the rigid robot dyna...
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