Backstepping adaptive hybrid force/position control for robotic manipulators

This paper presents a general design study of an adaptive force/position control using the (SFB) "strict-feedback backstepping" technique, based on passivity and applied to a robotic system. The advantage of the implemented control algorithm is that it imposes desired stability properties by fixing the storage, output stabilizing and Lyapunov candidate functions of the system. The parameter estimation for the design is made by the direct adaptive technique. The control law which is valid for various types of robotic architectures is very satisfactory when applied to a 4 d.o.f robot, consisting of one prismatic axis (axis 1), and three other rotary axes. The results obtained are satisfactory since the robot follows exactly the desired position and force trajectory. The trajectory and force tracking errors are negligible. The global stability of the system is also ensured.