Displacement Analysis of an Actively Articulated Wheeled Vehicle Configuration With Extensions to Motion Planning on Uneven Terrain

1996 ◽  
Vol 118 (2) ◽  
pp. 312-317 ◽  
Author(s):  
S. V. Sreenivasan ◽  
K. J. Waldron

This manuscript presents a displacement analysis of actively articulated wheeled vehicles on uneven terrain. These vehicles are distinct from traditional wheeled systems since they have the ability to actively adapt to variations in the terrain and they can actively influence the forces at the wheel-terrain contact locations. They also possess special mobility capabilities such as obstacle climbing and self-recovery from an over-turn failure. The problem of solving for the configuration of these vehicles on uneven terrain has been addressed in detail. The displacement analysis leads to multiple solutions due to the inherent nonlinearity in the position kinematic equations. Geometric reasoning has been used to identify the particular configuration that represents the “correct” vehicle geometry on the terrain. Applications of the displacement analysis algorithms to vehicle planning on uneven terrain have been discussed. An obstacle climbing maneuver of a three-module actively articulated wheeled vehicle has been described.

Author(s):  
Aliakbar Alamdari ◽  
Xiaobo Zhou ◽  
Venkat N. Krovi

The Articulated Wheeled Vehicle (AWV) paradigm examines a class of wheeled vehicles where the chassis is connected via articulated chains to a set of ground-contact wheels. Actively- or passively-controlled articulations can help alter wheel placement with respect to chassis during locomotion, endowing the vehicle with significant reconfigurability and redundancy. The ensuing ‘leg-wheeled’ systems exploit these capabilities to realize significant advantages (improved stability, obstacle surmounting capability, enhanced robustness) over both traditional wheeled- and/or legged-systems in a range of uneven-terrain locomotion applications. In our previous work, we exploited the reconfiguration capabilities of a planar AWR to achieve internal shape regulation, secondary to a trajectory-following task. In this work, we extend these capabilities to the full 3D case — in order to utilize the full potential of kinematic- and actuation-redundancy to enhance rough-terrain locomotion.


1999 ◽  
Vol 121 (1) ◽  
pp. 50-56 ◽  
Author(s):  
S. V. Sreenivasan ◽  
P. Nanua

This paper utilizes a kinematic-geometric approach to study the first-order motion characteristics of wheeled vehicles on even and uneven terrain. The results obtained from first-order studies are compared to those obtained from second order kinematic analyses, and special situations where the first-order analysis is inadequate are discussed. This approach is particularly suited for studying actively actuated vehicles since their designs typically do not include intentional passive compliances. It is shown that if a vehicle-terrain combination satisfies certain geometric conditions, for instance when a wheeled vehicle operates on even terrain or on a spherical surface, the system possesses a singularity—it possesses finite range mobility that is higher than the one obtained using Kutzbach criterion. On general uneven terrain, the same vehicles require undesirable ‘kinematic slipping’ at the wheel-terrain contacts to attain the mobility that it possesses on these special surfaces. The kinematic effects of varying the vehicle and/or terrain geometric parameters from their nominal values are discussed. The design enhancements that are required in existing off-road vehicles to avoid kinematic slipping are presented for a class of vehicles that include two-wheel axles in their designs.


Robotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 96
Author(s):  
Yankai Wang ◽  
Qiaoling Du ◽  
Tianhe Zhang ◽  
Chengze Xue

Hybrid mobile robots with two motion modes of a wheeled vehicle and truss structure with the ability to climb poles have significant flexibility. The motion planning of this kind of robot on a pole has been widely studied, but few studies have focused on the transition of the robot from the ground to the pole. In this study, a locomotion strategy of wheeled-legged pole-climbing robots (the WL_PCR) is proposed to solve the problem of ground-to-pole transition. By analyzing the force of static and dynamic process in the ground-to-pole transition, the condition of torque provided by the gripper and moving joint is proposed. The mathematical expression of Centre of Mass (CoM) of the wheeled-legged pole-climbing robots is utilized, and the conditions for the robot to smoothly transition from the ground to the vertical pole are proposed. Finally, the feasibility of this method is proved by the simulation and experimentation of a locomotion strategy on wheeled-legged pole-climbing robots.


2020 ◽  
pp. 16-22
Author(s):  
D.A. Dubovik

A method for quantitative assessment of the effectiveness of the running system of wheeled vehicles for the general case of curvilinear motion is proposed. An expression is obtained for calculating the coefficient of efficiency of the running system of a wheeled vehicle, taking into account the parameters of the power and steering wheel drives. The results of evaluating the effectiveness of the running system of an off-road vehicle with a wheel arrangement of 8Ѕ8 and two front steerable axles are presented. Keywords: wheeled vehicle, running system, power drive, drive wheels, steering control, effectiveness, coefficient of efficiency. [email protected]


Author(s):  
S. V. Sreenivasan ◽  
P. Nanua

Abstract This paper addresses instantaneous motion characteristics of wheeled vehicles systems on even and uneven terrain. A thorough kinematic geometric approach which utilizes screw system theory is used to investigate vehicle-terrain combinations as spatial mechanisms that possess multiple closed kinematic chains. It is shown that if the vehicle-terrain combination satisfies certain geometric conditions, for instance when the vehicle operates on even terrain, the system becomes singular or non-Kutzbachian — it possesses finite range mobility that is different from the one obtained using Kutzbach criterion. An application of this geometric approach to the study of rate kinematics of various classes of wheeled vehicles is also included. This approach provides an integrated framework to study the kinematic effects of varying the vehicle and/or terrain geometric parameters from their nominal values. In addition, design enhancements of existing vehicles are suggested using this approach. This kinematic study is closely related to the force distribution characteristics of wheeled vehicles which is the subject of the companion paper [SN96].


Author(s):  
Guillermo F. Diaz Lankenau ◽  
Lea Daigle ◽  
Samuel H. Ihns ◽  
Eric Koch ◽  
Jana Saadi ◽  
...  

Abstract This paper describes the motivation and development of a human-powered roll stabilization attachment for utilitarian two-wheeled vehicles. The proposed design has been built and tested by the authors in both on- and off-road conditions. It provides balance by providing a rolling platform underneath the two-wheeled vehicle (motorcycle) for the user to push against with their feet. This platform is placed under the driver’s sitting position and is towed from a three degree-of-freedom joint behind the front axle (i.e. one of the implementations uses a ball hitch joint). Fifty eight percent of the world’s motorcycles are in Asia Pacific, and Southern and Eastern Asia. In most of those countries, motorcycles greatly outnumber cars and many of these motorcycles function as utility vehicles. The uses of motorcycles include transportation of goods on the bike frame, transportation of goods on a trailer, and even pulling agricultural implements in farms. If no modifications are made to the motorcycle, at slow speeds operators of motorcycles must drag their feet on the ground and lightly push upwards as needed to retain balance. Attaching conventional outrigger wheels, similar to a motorcycle side-car, can negate some of the advantages of motorcycles that users value by: (A) preventing leaning into turns when rigid outriggers arms are used, (B) significantly increasing complexity and mass when outrigger arms mounted on suspension systems are used, and (C) increasing the vehicle’s width such that it can no longer travel between car lanes or between rows of growing crop. An additional design consideration for balancing motorcycles is the user’s need for quick conversion between a statically balanced vehicle and a vehicle can lean dynamically in turns, for example for someone who wishes to operate a motorcycle on farms but also travel quickly between agricultural fields. This conversion convenience is affected not only by the ease of attaching and detaching the balancing system but also by the ability to comfortably carry on the balancing system on the motorcycle even when it is not being used, such that it can be deployed when it is needed. This paper describes a design for a human-powered roll stabilization attachment that address these concerns and other identified user needs. It also provides with general equations to design similar human-powered roll stabilization systems for motorcycles.


Author(s):  
Liangyao Yu ◽  
Shuhao Huo ◽  
Xiaohui Liu ◽  
Xiaoxue Liu

Anti-Lock Braking Systems (ABS) have been developed and integrated into vehicles since it is invented more than thirty years ago. However, most of nowadays ABS are designed for multi-wheeled passenger cars, commercial cars and trucks. Due to the technical complexity and additional cost, ABS is not as common on two-wheeled vehicles, such as motorcycle, electric scooter, electric bike, etc. Study shows that injuries and deaths in relation to two-wheeled vehicles with ABS are significantly decreased. This paper is to provide a brief review of the state-of-the-art on the ABS configuration of two-wheeled vehicles.


Author(s):  
Jenelle Armstrong Piepmeier ◽  
Samara L. Firebaugh

In this paper we investigate the problem of controlling a scratch drive actuator that has two discrete modes of locomotion: forward motion in a straight line, and forward motion with fixed radius curvature. This type of device can be modeled as a two-wheeled vehicle (with the previously stated constraints). By alternating between these two modes of operation, the device can move along a variable-radius curved path. In practice, the robots do not move in a purely straight manner. This paper seeks to quantify the accuracy that can be achieved by switching between the two modes of locomotion. This type of low-level open-loop control facilitates the use of a higher level feedback controller designed for two-wheeled vehicles with a variable turning radius.


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