الفهرس 
Literature surveyOnly 14 pages are availabe for public view
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Abstract
The legged vehicles or walking machines have a potential advantage over wheeled vehicles of being able to travel in difficult terrains. Their capabilities in climbing steep, and inclined terrain as well as maneuvering around obstacles could be useful in environments hazardous to human such as areas where toxic chemical, radioactive materials or mining fields.
The previous literature showed that, the field of legged locomotion vehicles needs more studies and. Thus, this study proposed six legged vehicle, the kinematic and control of a proposed vehicle is carried out. The study of the gaits of motion and the relation between different legs during motion has been considered. The mathematical model of gait matrix, phase matrix, and duty factor are investigated. Their values are considered the basic data sheet for the microprocessor used to control the motion of the proposed legged vehicle.
The leg geometry is investigated and a leg designed on the principle of locking type gravitationally decoupled actuator (GDA) is proposed. A mathematical model describing the kinematics of the leg motion is developed, and the leg parameters (0,a,d,0) based on Denavit and Hartenberg matrix (DH matrix) are evaluated. This is followed by the formulation of geometric model to determine the relation between leg parameters and time. Also differential model describing the relation of the leg joints velocities and time is developed. A dynamic model based on Newtons Euler approach is developed to deduce the relation between the value of generalized force on leg joints and time.
A six legged vehicle is designed and constructed by using double acting actuators of 200 mm stroke. A low cost interface circuit consisting of demultiplexer, opto-isolators, a group of transistors, and a group of 2pole relays is developed to interact between the vehicle and the 6502 microprocessor. This microprocessor is used to process the controlled signal to the vehicle after the preparation of the control programs.
The experimental performance tests are carried out to determine the leg joints parameters (GH parameters). The obtained experimental results are compared with the analytical results, these comparisons show that there are certain deviation due to the accumulation of many error sources such as delay time , leakage in pneumatic actuators, and friction between guides, but the results show a satisfactory trend. Also the obtained experimental results are compared with similar results obtained by previous investigator. A close agreement between both results is noticed. The time constant for each of the leg axis is found to be as follows:
Time constant of rotational axis T= 1.7 sec.
Time constant of horizontal axis T= 0.8112sec.
Time constant of vertical axis T= 1.4 sec.
The delay time of each of the leg axis is found to be as;
Delay time for rotational axis 7 = 1.77sec.
Delay time for horizontal axis 7 = 2.247 sec.
Delay time for vertical axis 7 = 1.53sec.
An approximate overall transfer function for each of the leg axes is determined. The range of stability of each axis is determined by using the frequency response analysis.
The Nyquist contour show that the rotational axis is stable between 0<K<2, while the horizontal axis is stable between 0< K<1.35, as well as the vertical axis is stable between 0<K<2.1.
The calculated specific resistance is compared with the specific resistance obtained from previous investigations and an agreement value of specific resistance is noticed. The maximum regulating velocity of each axis of the leg is found to be as;
Vr =5.2.6 degree / sec.
Vh = 88.569 mm/ sec.
Uv =75 mm / sec.