The drive system of industrial robots is one of the six subsystems of robots (the other five are mechanical, perception, human-computer interaction, environmental interaction, and control), mainly responsible for providing power to robots, equivalent to the human cardiovascular system. The heart is responsible for providing a continuous supply of power, while blood vessels are responsible for transmitting blood to various parts of the body.
Its driving principle is to convert energy into "power energy" through various means, drive the joint movement of the robot, and drive the arm to the designated position.
Generally speaking, there are three methods, namely pneumatic drive, hydraulic drive, and electric drive, including the random composite drive of these three methods. Currently, electric drive is the most widely used in the industrial robot industry, including BORUNTE's industrial robots.
Explain the differences between these three types of drivers:
1. Hydraulic Drive: The hydraulic pump and cylinder convert hydraulic pressure into mechanical energy. The hydraulic pump is the power source of the entire system, and its essence is to convert the mechanical energy of the electric motor/engine into hydraulic pressure energy (hydraulic energy) through rotation or reciprocating motion, thereby driving the joint motion of the machine.
Hydraulic drive systems typically include components such as hydraulic pumps, hydraulic cylinders, and hydraulic valves.
2. Pneumatic drive: Using compressed air as the power source, the robot joints are driven by cylinders or pneumatic motors. Simply put, it is driven by mechanical power (such as electric motors, engines, etc.) to compress air into high-pressure gas (pressure energy), which is then transported through pipelines to cylinders or pneumatic motors to convert pressure energy into linear or rotational mechanical energy, driving equipment to move.
3. Electric drive: Using electrical energy as the direct power source, the equipment is driven to move through an electric motor. By utilizing electrical energy, the internal windings of the motor generate a magnetic field, which interacts with the rotor's magnetic field and rotates. The electrical energy is directly converted into rotating mechanical energy, which is then transmitted through a transmission device to drive the actuator (such as joints, limbs, etc.) to move.
Electric drive is widely used in industrial robots due to its high control accuracy, fast response speed, convenient digital control, high efficiency, and low energy consumption. For example, the BORUNTE robot uses electric drive, servo drive, gear, or belt transmission. The focus of this article is on how the drive system of robots operates with electric drive as the power source.
No drive is perfect, and electric drives also have their disadvantages, which are that they cannot directly convert power into usable mechanical energy and need to be combined with reducers to control the force required by the machinery.
The driving system of industrial robots consists of a motor and a reducer, which are generally connected using a reducer shaft or a wave generator. This structural design enables industrial robots to achieve high-precision and high-rigidity motion control, which is one of their core power sources.
1. Motor
The motor is the main power source in the drive system of industrial robots, responsible for converting electrical energy into mechanical energy and providing power for the movement of the robot. Common types of motors include DC motors, AC motors, stepper motors, and servo motors. Nowadays, AC servo drives are generally used to drive electric motors. Servo motors generally have high reliability and stability, and have a large short-term overload capacity. To add, our BORUNTE robots generally use servo motors.
'Servo' comes from the ancient Greek word for 'slave', which is the 'power core' of industrial robots, installed on each joint as a heart to provide power.
Its characteristic is absolute obedience to control signals. Specifically, when there is no control signal, the rotor of the servo motor is like being "fixed" and steadily stationary; Once it receives the control signal, it will immediately "respond to the command" and start rotating; And when the signal disappears, the rotor can "brake precisely" and stop immediately. The ability to "move wherever you point and stop as soon as you say" enables industrial robots to perform various fine operations.
2. Reducer
By reducing the motor speed and increasing the torque, the joint can move precisely to the designated position. Common reducers include harmonic reducers, cycloidal pinwheel reducers, and gear reducers. Harmonic reducers are commonly used at the joints of industrial robots due to their small size, large transmission ratio, high precision, and strong load-bearing capacity. RV reducers are widely used in industrial robots due to their high rigidity and efficiency.
3. Transmission device
The key component connecting the motor and reducer to the robot joints, responsible for transmitting power from the motor to each joint. Common transmission devices include synchronous belts, chains, gears, etc. The design of these transmission devices needs to consider the efficiency and accuracy of force transmission. For example, synchronous belts and chains are commonly used in the transmission systems of industrial robots due to their excellent transmission performance.
4. Connection method
In industrial robots, motors and reducers are usually connected through reducer shafts or wave generators. This connection method ensures efficient power transmission and system stability. For example, the wave generator plays a crucial role in harmonic reducers, achieving smooth and backlash-free transmission through its unique waveform design.
In short, the electric drive device for industrial robots is controlled by three loops: position loop, position loop, speed loop, torque loop, and motor execution. The position loop ensures that the robotic arm reaches the target position (outer layer control), the speed loop adjusts the speed during the motion process (middle layer control), and the torque loop precisely controls the motor output (inner layer control) to directly drive the motor.
The complexity of the intrinsic drive of industrial robots is no less than that of an empire. BORUNTE, a manufacturer specializing in the manufacturing of industrial robot bodies. Welcome to discuss more robot knowledge with me.