Johannes Lächele

Research Interest

Teleoperation is a very vast field that stretches over many different disciplines, including computer science, engineering, control theory, and many more. A teleoperation scenario can be defined when a device, e.g., a machine, robot manipulator or mobile robot, is being controlled by a human operator who is located in a different location than the device. Both parts are connected by a communication channel that transports the desired control input from the operator to the device and the sensor readings from the device back to the operator.

I am investigating teleoperation setups, where the operator controls a remote aircraft, namely a multirotor unmanned aerial vehicle (UAV) capable of vertical takeoff and landing (VTOL). The UAV is controlled using input devices that can also be found in regular planes and helicopters. Visuals typically include cockpit instruments and displays, plus live video streams delivered by one or more cameras attached to the UAV.

The separation of the operator from the aircraft adds additional challenges to the already demading task of controlling said aircraft. This is mainly due to the charateristics of the channel used between the operator and the UAV. Low overall channel capacity, latencies, noise, and jitter are the main factors that degrade the quality of controlling the UAV.

One reason for this can be the lack of information decreases the sense of "being there". This lack of situational awareness (SA) inevitably leads to a worsened performance in controlling the UAV and, in the worst case, the UAV to crash. Having said that, increasing the channel capacity or adding new sources of information should lead to a better SA and performance of the operator. My hypothesis is that presenting the motion of the UAV to the operator as feedback cue adds to the overall channel capacity. Therefore, the performance of the operator should increase.

However, it is not clear how the motion feedback needs to be defined in order to maximize the performance. In some cases motion feedback might even pose as a source of disturbance for the operator, worsening the performance.

In my PhD thesis I investigate the impact of motion feedback cues on operator performance. I hope that I can find initial evidence that suport my hypothesis that motion feedback helps increasing operator performance in some teleoperation scenarios.

Ph.D. project:
Motion feedback in tele-operation of Unmanned Aerial Vehicles (UAVs)

Introduction

Tele-operation of a remote vehicle is a challenging task, due to limitations of the remote sensors (e.g. weight, quality, power consumption), the transmission to the ground station (e.g. introduced noise and latency), and the display of this information to the operator (e.g. distortions, quality). These limitations may then lead to poor operator performance, increased workload, or even a loss of situational awareness. Usually, tele-operation setups do not provide motion feedback that lets the operator experience the motion of the remote vehicle. By providing motion feedback, the overall available information is increased, with the potential of increased operator performance. In tele-operation scenarios, the operator is located in a different location than the remote vehicle. This spatial decoupling grants a certain freedom in how the motion feedback can defined. Indeed, the motion perceived by the operator does not need to represent the motion of the vehicle. Instead the motion feedback could be defined to include information about the task. One example of task-related motion feedback is rotating the operator in roll depending on the lateral position error in a precision hover task.

Goals

First, find evidence for the effectiveness of motion feedback representing the motion of the remote vehicle (vehicle state motion feedback). Test the hypothesis of spatial decoupling that can be exploited to shape motion feedback in order to include task-related information. Finally, test the application of task-related motion feedback in a variety of tele-operation tasks.

Methods, Results, and initial conclusions

Participants completed a series of tele-operation tasks while experiencing different types of motion feedback, see Figure 1. We measured the performance and the control activity of the participants completing the task. Performance is defined as the accumulated error when completing a task; control activity is the combination of stick deflection and stick deflection velocity. We found that vehicle state motion feedback improves operator performance [1]. We argue that the increased performance is a result of increased disturbance rejection capabilities of the operator. This would be in line with results of vehicle simulation research [2]. In addition, we found a significant reduction of accumulated error for task-related motion feedback conditions, see Figure 2. Exploring task-related motion feedback is a promising approach to provide optimal feedback to the operator with the potential of overcoming the challenges posed by tele-operation.

References

Media

Work related to my master thesis (Diplomarbeit)

I have been working on a simulation environment called SwarmSimX. SwarmSimX is used within the  as a development and testing environment for a group of micro aerial vehicles (MAV). The focus of SwarmSimX is to provide a highly modular simulation framework that allows for simulating physical and visual properties of a virtual environment in real-time.

Below you can see a video of a quadcopter flying in the Multi-Agent-Lab (MAL) of the Max-Planck-Institute for Biological Cybernetics. The quadcopter is controlled by a program that uses the desired position and velocity of a recorded flight of a real quadcopter as control input.