In this paper a novel approach to the Cartesian Impedance Control problem for robots with flexible joints is presented. The proposed controller structure is based on simple physical considerations, which are motivatin...
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ISBN:
(纸本)0780382323
In this paper a novel approach to the Cartesian Impedance Control problem for robots with flexible joints is presented. The proposed controller structure is based on simple physical considerations, which are motivating the extension of classical position feedback by an additional feedback of the joint torques. The torque feedback action can be interpreted as a scaling of the apparent motor inertia. Furthermore the problem of gravity compensation is addressed. Finally, it is shown that the closed loop system can be seen as a feedback interconnection of passive systems. Based on these passivity property a proof of asymptotic stability is presented.
This paper describes a robust control design for automatic steering of passenger cars. Previous studies [1.2] showed that reliable automatic driving at highway speed may not be achieved under practical conditions with...
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ISBN:
(纸本)9783952426906
This paper describes a robust control design for automatic steering of passenger cars. Previous studies [1.2] showed that reliable automatic driving at highway speed may not be achieved under practical conditions with look-down reference systems which use only one sensor at the front bumper to measure the lateral displacement of the vehicle from the lane reference. An additional lateral displacement sensor is added here at the tail bumper to overcome this problem. The control design is performed stepwise: First, an initial controller is determined using the parameter space approach in an invariance plane. This controller is then refined to accomodate practical constraints. The performance and robustness of the final controller was verified experimentally at California Path.
Using the simulation software SIMPACK, the mechanical model of a freight car train running along a s-shaped track under high longitudinal pressure forces is presented. With the aid of simulation the freight car in the...
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ISBN:
(纸本)1853124923
Using the simulation software SIMPACK, the mechanical model of a freight car train running along a s-shaped track under high longitudinal pressure forces is presented. With the aid of simulation the freight car in the centre of the train should be judged with respect to several derailment criteria. The results are verified by comparison with measurements.
To improve the approximation capabilities of RBF networks, centers of adequate widths should be placed more densely on regions of higher than on regions of lower absolute second derivative of the function to be approx...
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To improve the approximation capabilities of RBF networks, centers of adequate widths should be placed more densely on regions of higher than on regions of lower absolute second derivative of the function to be approximated. This new concept is called second derivative dependent center placement. Using a test function especially designed to study this relationship, several RBF networks are designed and compared.
This paper presents a sliding mode control strategy for cars with an active steering system. The goal of control is to achieve a fixed dynamic relationship between the driver’s steering command and the vehicle’s yaw...
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This paper presents a sliding mode control strategy for cars with an active steering system. The goal of control is to achieve a fixed dynamic relationship between the driver’s steering command and the vehicle’s yaw rate in spite of a wide range of car and road parameters and varying operating conditions. The steady behavior should still be similar to conventional cars. Control design is based on a linear single track model and exploits the invariance property of sliding mode control. Implementational issues of the design process are discussed in detail in the form of robust continuous nonlinear controller to avoid chattering.
Highway automation is a promising approach to cope with increasing road traffic and congestions. An important control subtask of an Intelligent Vehicle/Highway system is automatic steering for lateral vehicle control....
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Highway automation is a promising approach to cope with increasing road traffic and congestions. An important control subtask of an Intelligent Vehicle/Highway system is automatic steering for lateral vehicle control. Due to system uncertainties and the wide range of operating conditions, state-of-the-art robust control techniques are required. This paper introduces two automatic steering controllers for cars driving under highway conditions. The control design is based on sliding mode control and robust state observation. It is shown that good tracking of a reference path, delineated either continuously or discretely, can be achieved with a minimum effort in sensing and without preview of the road curvature.
This paper establishes a general framework for the passing of mobile robots through narrow passages. Under such circumstances, the artificial potential method often leads to oscillatory motion (Koren et al. 1991) or e...
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This paper establishes a general framework for the passing of mobile robots through narrow passages. Under such circumstances, the artificial potential method often leads to oscillatory motion (Koren et al. 1991) or even lock-up situations (Khosla et al. 1988, Noborio et al. 1990). Sliding mode theory is utilized to examine the gradient of an artificial potential in the vicinity of the equi-distance line between the passage constraints. State-dependent and time-dependent smoothing methods are introduced to enable safe passing. The methodology is illustrated in experiments with the Siemens mobile platform ROAMER.
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