Pierre-Philippe Robet

A frequency approach for current loop modeling with a PWM converter

A new method based on a frequency approach is used to model a DC permanent magnet actuator driven by a pulsewidth modulated amplifier as a transfer function. This paper investigates two carriers used in industrial applications with analog or digital control. The accurate model presented takes into account the supply amplifier with the motor dynamics and includes the input control voltage sampling effect. Advantages and limitations of both carriers and control signals are discussed, and information about harmonic angles, magnitudes, and distortion are provided. The validation of the pulsewidth modulated model is carried out through simulations and experiments of both open and closed current loop systems with the effect of current ripple.

Estimation of the synchronous drive electrical parameters

Because of increasing joint speed and acceleration of complex mechanical structures such as rigid and flexible robotics manipulators, accurate models of joints with electric drives are needed to improve their simulation and their control. The authors proposed a new way to identify the electrical parameters of a robot driven by a synchronous machine. A closed loop identification of an inverse model which is linear in relation to the parameters is performed using least squares techniques and exciting trajectories of current. These current trajectories minimize a criterion which is function of the condition number of an observation matrix. Experimental results are given.

Global Identification of Mechanical and Electrical Parameters of Asynchronous Motor Driven Joint with a Fast CLOE Method

Abstract In many cases of new actuation of compliant controlled or bio-inspired joint driven robot, a global identification of electrical and mechanical coupled dynamics is required. This paper proposes a technique which mixes a closed loop output error method with the inverse dynamic identification model method, which allows for the use of linear least-squares technique to estimate the parameters. A first approach which has been validated on a DC motor achieves a decoupled identification of the electrical and mechanical dynamics but fails to make a simultaneous identification. A major improvement of that method is proposed to carry out the coupled identification of both mechanical and electrical parameters. A validation on an asynchronous motor driven joint shows the effectiveness of the new procedure.

Three phases PWM d-q frame harmonics calculation

This paper gives a modeling of a three phases PWM converter for two carriers used in industrial applications with analogue or digital control. The spectrum of these four types of configurations is calculated into the d-q frame which gives an easier interpretation of the harmonic components. Two calculations of possible unbalanced systems are presented with a validation by simulation, then an experimental validation through the current measurement of a synchronous machine is carried out.

Optimized force and co-manipulation control using stiffness of force sensor with unknown environment

This paper deals with force control and co-manipulation. From a classical control scheme using three closed loops with an external force control, we derive two new control schemes: the first is implemented in order to control the effort applied in a rigid environment and the second focuses on a co-manipulation control in an unknown environment. The proposed control law takes into account the stiffness of the sensor. This consideration is particularly important in the case of rigid obstacles. Experiments were performed with a one degree of freedom robot in order to verify the efficiency of our strategy and to compare the results against another existing controller.