This is a chapter that was cut from Applied Robotics 2 because of space issues. It discusses motor control issues in general and then moves on to build a 5-amp motor driver. The principles involved can be applied to much larger motor controllers. Though it is probably cheaper and easier to use the readily available Electronic Speed Control (ESC) s
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ystems on the market, a home-built ESC gives us (in theory) more control over the specifications. We can control the power rating (within reason), the PWM frequency, braking and regeneration features, acceleration curves, and other fine details. Also, many microcontrollers provide a nice PWM signal generated by hardware timers while the R/C control signal typically has to be created in software, using precious MCU cycles. There are two variables in the motor control state space - the actual motion of the motor, and the direction of the applied torque (from power applied to the motor). When the motor is stopped or moving forward and the power across the motor is in the forward direction (forward torque), then the control is said to be in Quadrant 1 (Q1), forward acceleration. A motor controller that only supports Q1 may consist of a single switch (transistor, IGBT, or MOSFET) and a clamp diode to protect it. When the motor is stopped or moving in reverse and the torque is in reverse, it is being driven in Quadrant 3 (Q3), reverse acceleration. A simple two-quadrant motor controller will operate in Q1 and Q3 and will consist of four switches in an H-Bridge configuration. This will be explored in more detail later. The motor moving forward with a reverse applied torque puts the control into Quadrant 2, reverse braking. Reverse motor motion with forward torque is Quadrant 4, forward braking. Motor controllers that support the...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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