inductance

An angular displacement sensor is an electronic component that uses angular changes to position an object. Applicable to automotive, engineering machinery, cosmic devices, missiles, aircraft radar antenna servo systems and injection molding machines, woodworking machinery, printing machines, electronic rulers, robots, engineering monitoring, computer-controlled sports equipment, etc. where accurate measurement of displacement is required. This paper introduces the principle of angular displacement sensor and its application examples.

Angle displacement sensor principle

The angle sensor is used to detect the angle. It has a hole in the body that fits the LEGO axis. When connected to the RCX, the angle sensor counts once every 1/16 turn of the axis. When turning in one direction, the count increases, and when the direction of rotation changes, the count decreases. The count is related to the initial position of the angle sensor. When the angle sensor is initialized, its count value is set to 0, and you can reset it by programming if needed.

Angle displacement sensor example

If the angle sensor is connected to any of the drive shafts between the motor and the wheel, the correct gear ratio must be included in the read data. Give an example of calculations. On your robot, the motor is connected to the main wheel with a 3:1 ratio. The angle sensor is directly connected to the motor. Therefore, its transmission ratio with the driving wheel is also 3:1. In other words, the angle sensor turns three weeks and takes the initiative to rotate one week. The angle sensor counts 16 units per revolution, so 16*3=48 increments is equivalent to one rotation of the drive wheel. Now we need to know the circumference of the gear to calculate the distance traveled. Fortunately, every LEGO gear tire is marked with its own diameter. We chose the largest wheel with a shaft, the diameter is 81.6CM (Lego uses metric units), so its perimeter is 81.6 × π = 81.6 × 3.14 ≈ 256.22CM. The known quantities are now known: the running distance of the gear is incremented by 48 divided by the angle and then multiplied by 256. Let us summarize. Let R be the resolution of the angle sensor (count value per revolution), and G is the gear ratio between the angle sensor and the gear. We define I as the increment of the wheel rotation angle sensor. which is:

I=G×R

In the example, G is 3. For the LEGO angle sensor, R is always 16. So we can get:

I=3×16=48

Every time you rotate, the distance the gear travels is exactly its circumference C. Apply this equation and use its diameter to get this conclusion.

C=D×π

In our example:

C=81.6×3.14=256.22

The final step is to convert the data-S recorded by the sensor into the distance -T of the wheel motion, using the following equation:

T=S×C/I

If the photoelectric sensor reads a value of 296, you can calculate the corresponding distance:

T = 296 × 256.22 / 48 = 1580 The distance (T) unit is the same as the wheel diameter unit.

Angle displacement sensor is actually applied

Using an angle sensor to control your wheels can indirectly reveal obstacles. The principle is very simple: if the motor angle sensor is configured to run and the gear does not turn, your machine has been blocked by obstacles. This technique is very simple to use and very effective; the only requirement is that the moving wheels cannot slip on the floor (or too many times), otherwise you will not be able to detect obstacles. This problem can be avoided if an idling gear is connected to the motor. This wheel is not driven by the motor but is driven by the movement of the device: during the rotation of the drive wheel, if the idler stops, you are experiencing obstacles. Things are gone.

Angle sensors are very useful in many situations: controlling the position of the arm, head and other moving parts. It is important to note that RCX is affected by accurate detection and counting when running too slowly or too fast. In fact, the problem is not in the RCX, but in its operating system. If the speed is beyond its specified range, the RCX will lose some data. Steve Baker has experimentally proven that a speed of between 50 and 300 rpm is a suitable range, and there will be no data loss. However, in the range of less than 12 rpm or more than 1400 rm, there is a problem that some data is lost. While in the range of 12 rpm to 50 rpm or 300 rpm to 1400 rpm, RCX occasionally has a problem of data loss.