Design of a haptic controller for excavators
Date
2009-03
Authors
Van der Zee, Lodewyk Francois
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
The input orientation of the excavators in use today usually comprises
two joysticks that control the actuator links individually. In order to perform
an excavation task, several different combinations of joystick inputs
are required, placing high psychomotor demands on the operator.
In training an operator this creates a steep learning curve, with a lengthy
training time and a reasonable amount of experience being required to
perform an excavation task skilfully. In this master’s thesis a haptic1 device
was developed, resolving input ergonomics and creating a single
input device capable of providing feedback to the operator. The design
and construction of the haptic device, with the related control scheme, is
presented and discussed. The control scheme combines position and rate
control, and relates all the actuator joint positions to a single end-effector
point. The control and ergonomic aspects of the haptic device were tested
and compared to the traditional two joystick control setup by means of
the implementation of a virtual excavator simulator. The simulation was
developed in MATLAB, and virtual excavator displayed in an openGL
window. The objective of this study was to evaluate the human factors
related to the input orientation. Ten inexperienced test subjects were recruited
to perform four sets of tests, where each test required a different
level of operator skill. The results indicated that, on average, the test subjects
had an increased level of performance after training on the haptic
device. These results strongly support the hypothesis that haptic control
simplifies the operational tasks required for operating an excavator.
1The word haptic means of, or relating to, the sense of touch, or tactile
Description
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009.
Keywords
Excavator kinematics, Denavit-Hartenberg transformation, Haptic devices, Dissertations -- Electrical engineering, Theses -- Electrical engineering