Robotics: Mars Rover and Robojeep (1995 – present)

 

Mars Rover and the Robojeep (1995 – present)

 
If the following definition of Robotics is used: Think, Sense and Act, then the enabling technologies for robotic applications have been studied at the TNO Physics and Electronics Laboratory for many years. The laboratory has expertise in the relevant sensor technologies, signal and image processing, sensor fusion, command & control, communication, operational studies, simulations, actuators, scenario analysis, and many other technology areas.
Robotics have advantages when used for tasks that are dull, dangerous, difficult or dirty.

Since the mid-1990s, the laboratory worked on a sequence of projects on developing Virtual Reality (VR) and robotic technologies and expertise. Moreover, simulation plays an important part in the navigation. In 1995, interdisciplinary expertise was developed to simulate a vehicle moving in unstructured terrain. At the time the goal was the navigation of a planetary rover in which case the time delay made direct steering by an operator impossible. Time delays to communicate with Mars are about 20 minutes. Therefore, simulation software was developed to plan a route and simulate whether the planetary rover is capable of following that route. The simulation included vehicle dynamics to estimate whether slopes in the terrain could be handled by the vehicle. This software is being implemented in the robotics testbed to check whether a computed-planned route is feasible for the testbed. Of crucial importance is the reality of the simulation. The coupling of the virtual environment and the real environment (VE/RE) was one of the major challenges of the project.

The rover in a realistic environment
The rover in a realistic environment

 

An electric wheel motor with control and power units
An electric wheel motor with control and power units

 

The moon or Mars rover controlled with Virtual Reality (1996)
The moon or Mars rover controlled with Virtual Reality (1996)

 

Those cross-cutting research activities were formalised in September 1997 when a robotics task force started with a master plan. In early 1998, work started on an unmanned ground vehicle, the Robojeep. This vehicle has as its mission to navigate in an unstructured environment and perform semi-autonomous useful observations in that environment. It was foreseen that such a vehicle has important military uses such as reconnaissance, landmine detection and IED clearing.

TNO's Robojeep (2000)
TNO’s Robojeep (2000)

The dunes behind the Laboratory provide a good test area for developing adaptive navigation strategies for (semi-)autonomous vehicles. A range of sensors acquires the information for navigation:

  • GPS with dead reckoning
  • Ultra-sonic sensors
  • Laser scanner
  • Stereoscopic camera
  • Odometers
Schematic design of the autonomous jeep
Schematic design of the autonomous Jeep

 

Steering actuator
Steering actuator
Hierarchical control
Hierarchical control

Teleoperations of the jeep need layer 2. The challenge was to be able to obtain a 3D-world model through these sensors and to develop the intelligence to navigate in this world model. The next layers need more environmental information and processing capabilities.

Stereo camera in the jeep
Stereo camera in the Robojeep

The figure below shows a stereoscopic image taken with the stereo cameras in the Robojeep at the testbed.

Stereoscopic image taken from the Robojeep
Stereoscopic image as taken from the Robojeep

Dedicated image processing determines the elevation concerning ground level to detect obstacles. The image below shows the elevation by overlaying a colour-coded elevation image.

Elevation indication by overlaying a colour-coded elevation image
Elevation indication by overlaying a colour-coded elevation image

 

Simulation for mission planning and execution
Simulation for mission planning and execution

MPEG – Remote-controlled Robojeep movie of the first remote-controlled test drive around the TNO laboratory on October 12, 1999. For safety reasons, a person in the car could operate an emergency brake.