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21.
Dean Karnopp 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1987,16(5):333-343
Large control forces in vehicle suspension systems or other vibration control systems may often be generated effectively by modulating the dissipation characteristics of an element using only modest control power. Most of the systems proposed in the past have involved hydraulic dampers, but a variety of other resistive elements can also be used. What is required is an efficient transducer from mechanical power to another form of power and a means to modulate a generalized resistor in the energy domain in question. Using bond graphs, it is shown that designs in the hydraulic domain can be transferred to other domains with possible benefits in certain cases. 相似文献
22.
通过实例说明两个具有拓扑共轭关系的混沌映射具有相同的Lyapunov指数.指出了仅仅使用Lyapunov指数作为混沌映射的密码学特性描述,具有一定的局限性.并利用混沌序列的伪随机特性,通过计算映射的自相关函数、互相关函数等随机数值特性,结合Lyapunov指数,分析了混沌序列的保密性能. 相似文献
23.
自由曲面上喷涂机器人喷枪轨迹规划方法研究 总被引:1,自引:0,他引:1
提出了一种自由曲面上的涂层生长模型及喷涂机器人喷枪轨迹规划方法,选取时间和涂层厚度作为优化目标,寻找喷枪沿指定路径的最优时间序列,通过求解带约束条件的多目标优化问题,找到了一条能使工件表面上涂层厚度方差最小且喷涂时间最短的喷枪轨迹。本文的优化方法将最优变量个数从一般喷枪轨迹规划问题中的6个(代表喷枪的位姿)减少为1个,从而大大简化了问题的复杂性。 相似文献
24.
25.
Sang-Gyun So Dean Karnopp 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1997,27(1):19-36
Small, narrow commuter vehicles have attracted considerable interest in recent years as a means to increase the utilization of existing freeways and parking facilities. However, conventional narrow track vehicles are likely to have reduced stability against overturning during hard cornering. A possible solution to this problem lies in vehicles which tilt toward the inside of a turn. Two different ways to achieve this tilt will be analyzed. For direct tilt control (DTC) an actuator forces the upper part of the vehicle to tilt. Steering tilt control (STC) uses steering to control the tilt as is done by motorcycle or bicycle riders. At low speeds, only the DTC system is effective while at high speeds the STC offers less lateral acceleration for the passenger during transient cornering and may seem more natural. The two methods of control will be studied separately and it will be shown that even though the same steady state tilt can be achieved with either system, the transient behavior of the systems is very different. It also will be shown that it is possible to switch from one system to the other at an arbitrarily chosen speed with virtually no transient effects even when the vehicle is not in a steady state. Regardless of which control system is active, the driver simply communicates his desire to follow the road by moving the steering wheel and the control systems take care of the tilting either by using the tilt actuator or by actively steering the road wheels. Thus the driver does not need to leam how to stabilize the tilt mode of the vehicle. 相似文献
26.
Theoretical Limitations in Active Vehicle Suspensions 总被引:1,自引:0,他引:1
Dean Karnopp 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1986,15(1):41-54
Vehicle suspensions in which forces are generated in response to feedback signals by active elements obviously offer increased design flexibility compared to conventional suspensions using passive elements such as springs and dampers. It is often assumed that if practical difficulties are neglected, active systems could in principle produce arbitrary ideal, behavior. It is shown, using a simple linear two degree-of-freedom suspension system, model that even using complete state feed back and in the case of in which the system is controllable in the control theory sense, there still are limitations to suspension performance in the fully active case. If the ideal suspension performance is defined based on low-pass filtering of roadway unevenness inputs, an active suspension may not offer much better performance than a partially active or adaptive passive suspension depending upon the values of certain vehicle parameters. 相似文献
27.
Dean Karnopp Professor of Mechanical Engineering 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1976,5(3):171-184
For the purposes of analyzing the stability and control properties of aircraft, automobiles, and ships, it is convenient to idealize the vehicle as a rigid body and to use a body-centered coordinate frame. A six-port bond graph is first developed which represents the nonlinear dynamics of a rigid body in a coordinate system rotating with the body. It is then shown how the graph simplifies if only lateral or longitudinal dynamics are studied. Finally, bond graphs for the type of stability studies in which the assumption of small perturbations permits linearization are shown for elementary models of automobiles and aircraft. 相似文献
28.
Dean Karnopp Professor of Mechanical Engineering 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1978,7(3):135-152
Vehicles which travel on uneven roadways or rough surfaces require power beyond that associated with air drag, rolling resistance or other sources of friction even though kinetic and potential energy may be conserved on the average. This is true because damped relative motions within the vehicle dissipate energy, and, even for nearly rigid vehicles, energy is lost at impact with the ground whenever the vehicle loses contact with the ground surface due to the finite downward acceleration of gravity.
Using elementary vehicle models, the nature and magnitude of the component of propulsive force associated with these energy loss mechanisms is estimated. In certain speed ranges, this force is found to vary dramatically with speed for several types of periodic roadway profiles studied. While the force due to unevennesss may be small compared to other forces for high-speed vehicles operating on smooth surfaces, it can be the major source of required power for off-road vehicles operating on very rough terrain. 相似文献
Using elementary vehicle models, the nature and magnitude of the component of propulsive force associated with these energy loss mechanisms is estimated. In certain speed ranges, this force is found to vary dramatically with speed for several types of periodic roadway profiles studied. While the force due to unevennesss may be small compared to other forces for high-speed vehicles operating on smooth surfaces, it can be the major source of required power for off-road vehicles operating on very rough terrain. 相似文献
29.
Dean KARNOPP 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1991,20(6):371-379
Instead of writing equations which when solved yield the response of a vehicle to an input such as the front wheel steer angle, one can often invert the equations so that a response quantity is specified as an input and a new set of equations is solved yielding the steer angle required as an output. Using these equations one can discover the input steer angle a driver would need to impose in order to accomplish a specific maneuver for various vehicles.
It is shown that there are many possible inverse equation sets and that the eigenvalues of the inverse equations are hard to interpret since they may have little to do with the vehicle parameters. The linear single-input single-output case is studied first to fix ideas using a simple example. For the bicycle model vehicle, it is shown that any vehicle may have unstable inverse equations depending upon the response quantity used. Extensions to nonlinear and multiple-input multiple output systems are discussed. 相似文献
It is shown that there are many possible inverse equation sets and that the eigenvalues of the inverse equations are hard to interpret since they may have little to do with the vehicle parameters. The linear single-input single-output case is studied first to fix ideas using a simple example. For the bicycle model vehicle, it is shown that any vehicle may have unstable inverse equations depending upon the response quantity used. Extensions to nonlinear and multiple-input multiple output systems are discussed. 相似文献
30.
Dean KARNOPP 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1987,16(5):355-380
A class of active suspensions is presented which provides near optimum isolation of base motion as well as zero static deflection for force disturbances using a simple type of feedback. The load leveling effect is rapid with the system stabilized using isolated mass velocity feedback both for a semi-active damper and for the load leveler. The system can be made energy conservative and fail safe since the system reverts to a reasonable passive isolator if the load leveling effect and even if the active damping effect is switched off. The system could be incorporated in automotive vehicles with some extension of the feedback control to account for several aspects of body motion. 相似文献