INTERACTIVE Driving AND OPERATION SIMULATION
At the Fraunhofer Institute for Industrial Mathematics (ITWM) BEC installed an interactive motion simulator based on an KUKA TITAN industrial robot with up to 1000 kg payload.
The 6DoF motion platform allows the use of series identical cabins up to a weight of 850 kg in an interactive scene, generated by 18 projectors inside a spherical projection-dome with 10 m cross-section.
The approach taken by ITWM in the implementation strategy was to develop all of the core components of the simulator as an open system and thus modifiable and scalable modules. This requirement could be met by circumventing a so-called “Black Box” models, or closed third-party solutions, in the components such as: system control, real-time simulation, motion cueing, visualization, NVH-simulation, and measurement systems on operator.
The RODOS® System allows the simulation of various vehicle types, analysing aspects such as energy efficiency, productivity, durability, and reliability. These aspects have non-stationary characteristic and are acting over long time periods. Thus, it is required that all external inputs acting on the vehicle are considered and properly represented. The external inputs include not only vehicle loads but also direct inputs originated from the human operator.
Advantages, benefits, higlights
- The simulator can be operated with series identical cabins up to a weight of 850 kg.
- Large translations and tilt angles allow to develop new applications compared to Stewart-Gough platforms.
- Visual simulation with 11520 × 3600 Pixel (18 projectors), 120 Hz active stereo projection possible
- The motion cueing algorithms can be easily adapted to the simulation task.
- Import options for various realtime vehicle models such as DSpace ASM®, Simpack RT® or VIGrade CarReal-Time®. Models of hydraulic, electronics, etc. can be integrated with Matlab/Simulink® as middleware.
- Own real-time tire simulation with CDTire® and coupling to the simulator
- Researching of the effects of operator experience on development goals such as productivity, durability and reliability
- Design of driver and operator models for complex scenarios
- Research into the cognitive load without disturbing environmental influences
- Ad hoc variant tests of different vehicle configurations
- Maximum acceleration up to about 5 m / s²
- Use of electrodynamic shakers (total of 3 kW) for a frequency band from 5 Hz to 200 Hz
Intelligent adaptive interface systems in farm tractors
For farm tractors, the possibility of universal application is considered, and therefore it needs to be accompanied by appropriate equipment. The diversity of possible work and the appropriate equipment for tractors results in many different operating scenarios. As a result, the requirements for variability of operation with farm tractors are very high. Common operating scenarios are considered when developing the interface systems (the entire set of all interface elements and interface modules), and this generally leads to compromises in the design. These solutions based on compromise must illustrate the complex diversity of functions in all operating scenarios, and therefore constantly present the driver with new challenges in assessing the operating logic, the operating sequences and the allocation of interface elements (e.g., individual setting devices, keys, buttons and displays) to the functions.
However, an intelligent interface system can provide the user with the ideal interface system in each case through the adaptivity of interface elements in terms of the parameters of position, shape, color, graphics and torque in individual operating scenarios, in order to reduce the complexity and increase operability.Within the framework of this project at the Agriculture Institute at the University of Hohenheim, we intend to investigate the shape, operatability and blind differentiation capability of haptic touch setting parts subjected to vibration in off-road use, particularly with regard to adaptivity parameters.
In addition, we intend to investigate the operability and reading capacity in the ever-increasing use of touch display technology in agricultural machinery, whether it be a terminal in the agricultural machine itself, on a smartphone or on a tablet. This will enable us to develop a catalog of guidelines that specifies the requirements for haptic and software-based interface elements under specific off-road conditions.
A vibrating platform will be mounted on a robot arm to conduct the subject group tests. The trajectories of the robot arm have been determined based on a range of values recorded on the floor of the cab of an actual farm tractor moving over land with various consistencies. Figure 1 shows the conditions and measuring points on an actual standard farm tractor.
Figure 2 shows the test rig construction. The acceleration values on the actual cab floor (Figure 1) of the farm tractor are used to derive the trajectory of the robot arm in such a way that the acceleration values on the test rig platform correspond to the cab floor on the actual system. Acceleration values on the seat surfaces are also measured and compared to provide additional validation.
The use of a robot arm for this test rig assembly is particularly suitable, as it not only simulates vibration motion, it also allows us to illustrate all movements on steep slopes, as a result of the degrees of freedom of the arm. A standard cab can be mounted on the robot arm and the environment can be displayed for additional holistic investigations of operating systems and driver comfort. Associated with this modification, we could simulate the real-time control of the trajectories of the robot arm based on the operating signals generated by the subject group. In order to do this, the behavior of the entire farm tractor system with regard to operating signals and ground consistency must be saved and made available to the test rig.
Dipl.-Ing. Timo Schempp
University of Hohenheim -
Institute of Agricultural Engineering
Garbenstr. 9 - D-70565 Stuttgart