Introduction

The goal of the project is to develop a new type of steering systems for 4 wheeled vehicles which gears up vehicles with maximum maneuverability. Important aspect for the project was to consider the parts of conventional steering systems for development purpose. As a result, a steering system was developed for diamond configuration vehicles as well as square configuration vehicles. For the project, I worked on research, conceptualization, modelling and drafting.

To start with, there are 4 types of steering modes any vehicle can achieve- normal steering mode, 4 wheel steering mode, crab steering mode and zero turning mode. The diagram shows 4 types of steering.

There are 2 types of configuration for vehicles- diamond and square configuration, which are decided based on the position of wheels. Diamond configuration has one wheel in front, 2 wheels in middle and one wheel in the back. Square configuration is most common which has 2 wheels in front and 2 in the back.

Solution

For reaching the solution, conventional steering systems and the parts of it were studied to understand the function of parts and mechanics of steering. Most conventional steering systems have rack and pinion assembly to convert rotational forces into longitudinal forces and a steering rod on suspension upright/knuckle. The movement of 4 bar mechanism is governed by ackermann geometry which makes sure that wheels do not slip sideways while taking a turn.

The new design makes use of basic building blocks of conventional steering systems which are rack and pinion to reach the objective. The overall solution was derived in steps, starting from zero turning system for diamond configuration which is simplest of all.

Later on, the system was extended to achieve crab steering for diamond configured vehicles. In the last stage, taking inspiration from steering system for diamond configuration, based on the same components, steering system for square configured vehicles was devised.

The basic principle is to apply calculated and interconnected forces on each of the wheel so as to induce desired angular motion in each wheel. Due to interconnection of forces, each wheel rotates with respect to other wheels thus giving a collective output. To facilitate the different motion of pinions needed (angular and translation), a slideway and key are added to assembly which, based on the requirement, make the pinion rotate or translate in slideways.

Designing a mechanism with mechanical linkages opens up new directions with hydraulic and pneumatic systems. Thus the steering system in this project can also be designed using hydraulic or pneumatic linkages by transferring forces through a combination of valves and fluid lines to different wheels.

Introduction

A machine press is a tool used in the manufacturing industry to deform a workpiece under the application of pressure. This project is a design of a new type of press mechanism to match the capabilities of servo presses at low costs. In turn, just like servo presses, the new design will have features of hydraulic and mechanical presses at a relatively low cost. For the project, I worked on research, ideation, conceptualization, modeling and drafting the patent.

Problem

In general, there are 3 types of presses- mechanical presses, hydraulic presses and servo presses, each having their own set of advantages, disadvantages. Mechanical presses are simple, suitable for fast, high-volume production but have fixed stroke length and requires a flywheel to operate. Hydraulic presses can generate full press capacity at any point in stroke but are more complex. Servo presses are most versatile which combine speed of mechanical presses and flexibility of hydraulic presses but are costly. The objective of this project was to develop a solution that can achieve advantages of all three types of presses.

Solution

When shuttles translate, every point on connecting rod traces an ellipse except one position which traces a circle. Here the input becomes the translatory motion of shuttles and the output is the circle traced by the rod. Completely reversing this operation, if a circle is traced, then translating motion of shuttles is achieved as an output. This principle forms the basis for the solution. In other words, with one circle tracing, we will get 4 strokes in different directions from 2 shuttles. If we attach a high torque motor, which provides a circular output and use it as an input to this mechanism, then we get 4 working strokes in one revolution of the torque motor shaft.

Adding versatility

Variable stroke length

Stroke length is how far an actuator travels in an arm of the mechanism. In this case, as high torque motor is the input to mechanism, the specific point on the connecting rod traces circle irrespective of length of arms. Which means with different length of arms, the mechanism will still operate in the same way and will give different stroke lengths.

Increasing number of strokes achieved

Variable stroke angle

Due to the modular nature, the press assembly can be positioned in the way needed without affecting the working of the total assembly. At the same time, it becomes easier to use the assembly for different products due to the modular nature, as many of the parameters can be customized as per the need.

To understand how each steering mode is achieved, please check out the Patentscope link.

Introduction

The goal of the competition was to successfully design, build and test an off-road vehicle. The goal of suspension was to safeguard the vehicle’s members, and driver from off-terrain shocks, and provide suitable vehicle handling conditions. For the same, suspension kinetics, kinematics, shocks, and dampers were studied, and a suitable system was designed, simulated and then built. The system was then tested on the endurance track and suspension track. As a result, the vehicle and suspension endured 4 hours of off-roading event successfully.

Design

Design kinetics- how the plane of a wheel moves with suspension travel

Stress analysis- What are the stresses induced and is it safe?

Manufacturing

Validation

Failure Mode Effect and Analysis

Design Failure Mode and Effect Analysis is a systemic way to analyse the design to identify where and how it is most prone to fail and to assess the relative impact of different failures. The analysis was carried out for the whole vehicle and respective S-O-D (Severity-Occurance-Detection) and RPN (Risk Priority Number) were calculated. A Corrective action plan was also suggested to reduce the RPN.

Testing

The suspension and overall vehicle was tested at the testing facility of Natrax in Madhya Pradesh, India, where vehicle was subjected to harsh conditions. In the end, the buggy ran 4 hours of endurance race on the off road track at the facility. The vehicle that we built sustained those conditions but also showed points of improvement for next year.