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The problem of vehicle stability in emergency maneuvers has attracted a lot of research effort recently. Perhaps the most effective contributions made in this area were devoted to the control of vehicle yaw rate either by active steering or differential braking control systems. Each control technique has its own limitations that make it ineffective in some particular situations. This paper introduces a combined steering and braking control strategy using a fuzzy logic inference system. The proposed controller uses the estimated coefficient of friction (μ) to organize the combined control action. Computer simulation using a comprehensive vehicle model is used to illustrate the strengths and limitations of various control strategies.

High center of gravity vehicles need to be stiff in roll to prevent excessive roll angles when cornering. In some cases, there may be more roll compliance in the tires than in the suspension itself. For this reason, the conventional shock absorbers may not provide effective damping of the roll mode. The result is that wind gust and roadway unevenness disturbances can cause large swaying oscillations. Here a novel use of automatically steered wheel is proposed to augment the damping of the roll mode. Either the front wheels, the rear wheels or both can be steered using a simple feedback scheme using sensed roll rate. The scheme is effective in specific speed ranges and stabilizes the roll mode without introducing disturbance moments from roadway unevenness as shock absorbers do. There is a theoretical advantage to coordinated steering of both front and rear wheels but this level of complexity may not be practically justified.

The effect of exhaust system configuration upon performance of two-stroke engines is explored. Computer predictions of gas dynamic behavior in the exhaust pipes are compared to experimental results of real pipe tests. Predicted pressure, velocity and temperature histories at key points in the exhaust system explain the relative power differences for the test pipes. Predicted volumetric flow rates show the effectiveness of exhausting gases at larger pipe cross sectional areas in reducing noise output. The application of the computer predictions to a Yamaha RS 100 offers an explanation for the experimentally measured loss of power at mid-range engine speeds encountered using one of the two test pipes. A relative comparison of the two systems shows that the differing pipe geometries cause predicted pressure and velocity histories to change. These changes are correlated to actual power curves.

A series of examples, involving normal mode representations of a flexible railcar and various suspension models, is presented illustrating the use of bond graph techniques for assembling a structural dynamic system model from component models. Bond graph techniques are related to other methods for achieving the same goal, and the unique features of bond graph techniques are pointed out. Not only does the bond graph provide a graphical representation of the organized system equations, but also it allows the use of ENPORT programs for automating the process of manipulating the component relations into an explicit-state space format suitable for simulation or analysis. Nonlinear and active systems which interact with structural dynamic components are readily handled using bond graph techniques.