Entwicklung eines haptisch unterstützten Bedienkonzepts für Hydraulikbagger

In mobile hydraulic machines such as excavators, haptic human-machine interfaces are currently not in use. Today, the machines are operated by mechanical-hydraulic joysticks. Each joystick axis controls a single hydraulic actuator. This leads to operational concepts which are not very easy to use. Due to the fact that electro-hydraulic systems with electronic joysticks are available for serial applications, alternatively, more intuitive operational concepts have become feasible. These concepts can be enhanced further by adding haptic driver-assistance systems. The aims of haptically enhanced operational concepts are to increase the efficiency of the human-machine interaction by providing driver-assistance systems, reducing operating errors, and shortening the time required for inexperienced drivers to learn how to operate the machine.
In this thesis, a haptically enhanced master-slave operational concept for a hydraulic excavator is proposed. The concept includes a conceptual design for intuitive, active operating-elements as an alternative to conventional joysticks. It also includes bilateral control-architecture for the complete system, consisting of the hydraulic excavator and the active operating-device. The device resembles the kinematic chain of the excavator’s manipulator. This allows for intuitive operation of the machine. The operating device is actuated to implement position control of the device. This is necessary to permanently synchronize the operating device and the position of the hydraulic manipulator. The main idea entails position controllers for both the excavator and the operating device where both control loops output the reference position to one another. More specifically, two position-controlled systems are placed in a feedback loop with each other. The human operator acts as an input disturbance to the operating device. This approach allows stable teleoperation of the machine and gives the operator haptic feedback of the manipulator’s inertia. The Internal Model Control (IMC) methodology is employed to design the position controllers for both the hydraulic manipulator and the operating device. Therefore, a simplified design rule for the IMC filter and a novel anti-windup approach for models with pure integrators are proposed.
A second aspect is the utilization of the active operating-device’s actuators to implement haptically enhanced driver-assistance systems. These systems support the driver as he performs his working tasks (e. g. leveling assistance, slope cutting, and workspace limitation) through tactile forces fed back by the operation element.
In order to verify the operational concept and the haptic assistance systems, they were exemplified on a virtual-reality excavator simulator and on an experimental excavator equipped with electronic pilot-valves, rapid-control prototyping hardware, and sensor systems. To test the concept on the prototype, commercially available devices, namely a SensAble Phantom Omni and a 3Dconnexion SpaceBall 5000, were used. Measurement results are given.
Experiments with test drivers are performed to evaluate the proposed operational concept and the haptically enhanced driver assistance systems. The experiments confirm the usability of the operational concept and the benefit of the haptic assistance systems.