In this paper the control of flexible joint manipulators is studied in detail. The model of N -axis flexible joint manipulators is derived and reformulated in the form of singular perturbation theory and an integral manifold is used to separate fast dynamics from slow dynamics. A composite control algorithm is proposed for the flexible joint robots, which consists of two main parts. Fast contro...

The objective of this paper is to develop an outer sheath for flexible endoscopic manipulators. This sheath can switch two states including flexible and rigid, and make a rigid curved path for inserting manipulators. The flexible mode can be curved into a required shape. The rigid mode can hold the shape of the sheath, and then keep the path for instruments. Through the managed path, the flexib...

Robust nonlinear control of flexible-joint robots requires that the link position, velocity, acceleration, and jerk be available. In this paper, we derive the dynamic model of a nonlinear flexible-joint robot based on the governing Euler-Lagrange equations and propose extended and unscented Kalman filters to estimate the link acceleration and jerk from position and velocity measurements. Both o...

Hybrid position/force control enables a robot to apply specified forces to a constraint while moving along a prescribed path. Flexibility of the motor transmissions (joint flexibility) is a major concern in the design of hybrid controls, particularly with regard to system stability. While much work on hybrid control has been toward the development of advanced schemes specifically for flexible-j...

An actuator is required to change its speed and force depending on the situation. Using multiple actuators for one driving axis is one of the possible solutions; however, there is an associated problem of output power matching. This study proposes a new active joint mechanism using multiple actuators. Because the actuator is made of a flexible bag, it does not interfere with other actuators whe...

This chapter focuses on the dynamic control issues of lightweight robots as well as flexible joint robots. The goal is to increase the bandwidth and the accuracy of the trajectory tracking control. Besides the joint flexibility, the control design considers the dynamics of the electric motor in AC-form i.e. the three phase permanent magnet synchronous motor (PMSM). The final system model is a f...

This paper considers improving the tip regulation performance of a joint-PD controlled single-link flexible manipulator by introducing nonlinear strain feedback. The controller is developed by applying Lyapunov’s direct method. The stability of the closed-loop system is theoretically proven based on the partial differential equations (PDE’s) which govern the motion of the flexible robot, instea...

The trajectory-tracking control of a typical industrial robot with six revolute joints is studied, where the joint flexibility is taken into account. An explicit form of the control law is obtained by using the composite control technique. The stability of system is discussed. The global convergence of tracking error can be reached by tuning the controller parameters. This method has a unique a...

In this paper we show the identification of the dynamic parameters of a redundant flexible joint robot with a flexible bearing in the first joint. The bearing leads to distortions of the link velocities measured by gyroscopes. The bearing flexibility is not modeled explicitly, resulting in a very simple model. For the joint positions encoders are used. We show how to pack the calibration proble...

In this paper, a NCGPC (Nonlinear Continuous Time Generalized Predictive Control) is proposed for a single-link flexible joint manipulator. This control is developed by using a property of NCGPC, the demonstration that the selection of particular design parameters, such as control order and predictor order leads to well-known feedback linearization. Simulations are presented in order to illustr...