Telemanipulation with force feedback basics

To create the energetic connection between the human interface and remote robot , a control architecture is used. There are various architectures that can be used to build a telemanipulation system, each with different properties. The Position-Force architecture a relatively simple architecture, and it is intuitive to understand how it works. In this video, we explain how the Position-Force architecture works. We also introduce that we can consider a robot to behave mainly as a mass and what the consequences are for controlling a robot.

For the kinaesthetic approaches in telemanipulation, achieving full transparency (See introduction to telemanipulation) is made challenging by a number of factors. One of these factors are the dynamics of the human interface and robot. In this video, we explain why device dynamics can get in the way of achieving full transparency. We also introduce ‘power ports’ and ‘rigid connection model’.

For the kinaesthetic approaches, achieving full transparency (See introduction to telemanipulation) is made challenging by a number of factors. One of these factors are time delays in the communication channel. In this video, we explain why time delays can get in the way of achieving full transparency.

To get an idea of the effect of time-delay on the ability of an operator to perform a task, have a look at the attached videos. In these cases the time delay is in the visual channel, but you wil get an idea of the effect:

To create the energetic connection between the human interface and remote robot , a control architecture is used. There are various architectures that can be used to build a telemanipulation system, each with different properties. The Position-Force architecture a relatively simple architecture, and it is intuitive to understand how it works. In this video, we explain how the Position-Force architecture works. We also introduce that we can consider a robot to behave mainly as a mass and what the consequences are for controlling a robot.

The position-position architecture is the oldest, and most applied architecture to achieve an energetic connection telemanipulation system. It was one the first architectures to be applied as it works with position controlled robots and does not require direct control of the forces. The position-position architecture achieves the energetic telemanipulation connection between the human interface and remote robot by using two feedback controllers. In this video, we start with introducing ‘feedback control’. Based on this, we explain how the position-position architectures realises the energetic connection.

There are various control architectures that can be used to create the energetic connection between the human interface and remote robot in a telemanipulation system. When you have a perfect model of the system, the four channel architecture is able to achieve perfect transparency. The four channel architecture is based on ‘feed forward control’ which is first explained in the video. Based on this, we explain how the 4-channel architecture realises the energetic connection.

In this video we wrap up the basic telemanipulation control architectures that are discussed in detail in the other videos. The video gives a comparison of their behaviour based on the relations between the forces and velocities, and the conditions for perfect transparency. In addition, “dynamics compensation” is introduced as a third basic controller structure to reduce the effect of device dynamics on the transparency.

In robotic systems, instability is related to energy generation caused by, for example time-delays. A system that does not generate energy, and is stable as a consequence is called passive. Passivity is a useful tool to deal with problems related to energy generation. In this video, we explain the basic principles of passivity and how passivity can be used to create stable controlled systems.

The communication between the human and robot side of a telemanipulation system inherently introduces time delays. Because of time-delays, otherwise stable systems can become unstable. Time Domain Passivity Control (TDPC) offers a practical way to quarantee passivity and thus stability of (telemanipulation) control systems. In this video, we explain the based concept. In the “Passivity Oberver” and “Passivity Controller” videos specific implementations of the passivity observer and controller are explained.

In Time-Domain Passivity Control, the passivity of the system is monitored to determine when the system loses passivity. The method to measure passivity is called the Passivity Obverer (PO). In this video, we describe one of the methods to monitor, or observe, the passivity of a system – the energy tank based method. With the energy tank based method, you do digital bookkeeping of the energy that is absorbed by the system. You use this information in real time to check if the systsems meets a passivity criterion.

In Time-Domain Passivity Control methods, the passivity of a system is monitored in real-time. The method to monitor the passivity is called the “Passivity Observer”. In this video, we describe one of the methods to monitor, or observe, the passivity of a system – the Time Delay Power Network method. The Time Delay Power Network can be applied to an (in principle) power continuous part of the system that is affected by time delay. We start with explaining what power continuity, and based on this explain how the Time Delay Power Network method can be used to monitor the passivity of a system.

In Time-Domain Passivity Control, the passivity of a system is observed and controlled in real-time. Once you have determined that the system does not behave passive, a method is needed to make sure that the system return to passive and thus stable behaviour. In this video, we explain one of the methods to control the passivity of a system – by adding the necessary damping in real-time. The damping is computed to exactly dissipate any generated energy such that the system does not generate energy and behaves passive again.

In Time-Domain Passivity Control, the passivity of a system is monitored in real-time. When a system does not behave passive, the is releasing more energy than it has absorbed. One of the methods to stop the non-passive behaviour is to directly stop energy release. In this video, we explain how this can be done.

In Time-Domain Passivity Control, the passivity of a system is monitored in real-time. To monitor the passivity, you need to measure energy and power. In discrete-time systems, this requires special attention. In this video, we explain why measuring energy in discrete-time can be inaccurate if done naively, and how and when energy can be measured accurately.

In Time-Domain Passivity Control, the passivity of a system is monitored in real-time. In other videos, we have introduced methods to measure energy, observe and control passivity as well as different telemanipulation control architectures. In this video, we discuss the application of Time-Domain Passivity Control on the Position-computed Force architecture.