Virtual Prototyping and Real-Time Simulation of Heavy Equipment Manipulators Including Elastic Deformations and Hydraulics

The efficient and unerring development of sophisticated manipulation machinery strongly relies on the efficient use of CAE (Computer Aided Engineering) methods. Meanwhile these methods more and more spread into areas, which have been so far domains of so called VR (Virtual Reality). This encompasses the design aspect as well as the simulation of an already defined device under given workload and working environment along with the option for an easy adaptation to any change of the requirements.

Whereas the efficient and reliable simulation of the real world behaviour of rigid body models is state of the art even for complex machines the inclusion of elastic effects especially in real time simulations is still the cutting edge of technical simulation. This includes the elasticity of the multibody structure itself as well as the influence of compliant hydraulic subsystems coupled to the deformable structure.

The paper looks at the off-line as well as at the real-time simulation of elastic hydraulically driven heavy multi-axes manipulators like e.g. concrete pumps. The application of the tools to support the development of heavy machines will be discussed. Along with the simulation of the operation behaviour the work done also focuses on the support of the advanced man-machine-interfaces used to operate the device.

Various modules have been developed and proved to easily include hydraulic components like interfaces to Hydraulic Simulation Software Systems, like e.g. DSHplus into the description of the dynamic behaviour of the basic elastic mechanical structure. There is also a strong need to run simulation programs for the devices under consideration in real-time mode. Therefore strategies were developed and applied to various examples to simplify the respective model architectures along with the simulation algorithms in order to allow real-time simulations reflecting the actual properties of the device with still a high precision level. The models created are suited to be converted into a 'real-time code' with the option to be uploaded onto the microcontroller of the machine hardware.

The application of the methods presented will be explained at an example based on real world equipment including on-line animation.