- How dose the servo motor work?
- servo motor can keep the shaft position ? That means: stars servo motor, then stop servo motor, then the shaft can keeps the position. Servo motor needs current to keep this position ?
- The Torque of HS-422 Servo Motor is 4.1(Kg-cm), so it keep the shalf position is the same torque ?
Thanks. The answer is great help for me. I still have some questions.
For example. The servo motor’s shalf rotates clockwise 90 degrees, then rotates counterclockwise 180 degrees .
- suppose the servo motor controller connecting the motor already, what do the signals need to sent to the motor controller for controlling the degree and the direction. It is TTL?
- I note that some Servo Motor Controllers have **USB **and some don’t . For Servo Motor Controllers with USB, I have to use PC (like laptop) to connect the servo motodr controller, and sent signals to them. ?
- If I want to** program **a robot/ servo motor, I have to use the microcontrollers / servo controllers that own USB ? I need to connet the PC to microcontroller / servo controller in order to programming.
Thanks. I have more questions.
- (I confuse the relationship between RPM and sec/60 degree) I know 200 rpm means in one minute the shaft of motor turns 200 revolutions
1.15 sec/60 degree equates how many rpm ?
2 At SPG785A-4.5 Servo Gearbox (5:1) Kit. The Maximum torque is 915 oz-in/66kg-cm. Supossing use it as an elbow in a arm. The section of arm (from elbow to wrist) is 30 cm(one foot). Then the maximum load that the arm can pick up is = 6.6/30 = 0.22 kg. Is it correct ?
Hi Cbenson
Which books can teacher me
1.Basic robot knowledge,
2. How to program with c language.
3 Mechanical knowledge including how to make an arm.
Hi Benson
From following microcontrollers, which I can use c language ?
32 Bit Microcontroller
Arduino
BasicATOM
BasicX
NanoCore
Parallax
PICAXE
Pololu Orangutan
Miscellaneous
Hi Benson. Thank you for your answer.
I have some questions here.
1.What is meaning “standard size” Hitec servos
2.If I buy a “SPT400 Gear Drive Tilt System (5:1)” robotshop.ca/servocity-sp…box-5-1-4.html
Could I mount “HS-805BB Giant Scale Servo Motor” on it ? robotshop.ca/hitec-hs805BB-servo-motor.html
3. could I chang the gear in “HS-805BB Giant Scale Servo Motor” in order to get more torque ?
4.Stall current is meanning “load current” ?
“HS-785HB Winch Servo Motor” 's stall current is 1500 mA at 4.8 V robotshop.ca/PDF/HS-785HB.pdf
“HS-805BB Giant Scale Servo Motor” 's stall current I can not find at robotshop.ca/hitec-hs805BB-servo-motor.html
I guess it is more than 5000 mA.
My device maybe runs at least 2"HS-785HB Winch Servo Motor"s and 2 "HS-805BB Giant Scale Servo Motor"s. and I need control the speed and the direction (clockwise and count-clockwise). if I use “Arduino Uno USB Microcontroller”
What motor drivor I should choose ?
5. what power supplyer I should choose ? could I use the power box of PC computer. It has 5V DC with big current.
- All of the hitec servo motor’s rotation is 180 degree ? In some case, more than 180 degree rotation is need. some companies provide servo motors with more than 180 degree rotation like 300 degree.
Does the rotation of hitec servo motors change to 270, 360 degree or more, by replace the potentiometer in servo moter without guarantee ? - I note that the SPG785A-4.5 Servo Gearbox’s rotation could be different from 630,420,315,and 252 degree because of the rocation of 785 servo motor is three and half turns.
Could I change the external potentiometer to change the rotation in order to get about 270, 360 degree totation at 3/8" shalf in SPG800A Gear Drive Pan System ? - What is the torque of the 3/8" shaft in SPG800A Gear Drive Pan System (5:1) ?
What is relationship beteen 285 (Power gearbox torque 285 in-oz ) and 1,700 (The 1,700+ oz-in. of torque from an inexpensive 1/4-scale servo can be easily done with the new SPG805A Servo Power Gearbox.) ? robotshop.ca/servocity-spg800a-gear-drive-pan-system-5-1-4.html - What is the vertical and horizontal load of the HS-422 Servo Motor and HS-425BB Servo Motor ?
What is the life of the HS-422 Servo Motor and HS-425BB Servo Motor if them keep continual running ?
Coleman talked me “We currently do not offer encoders specifically for servo motors (since most can only rotate 180 degrees and provide position feedback, an encoder is usually not necessary.”
My question is: How does a servo provides the postion feedback ?
If run a wheel with a continuous ratation servo HSR-1425CR or I chang HS-755HB to a continous ratation servo how do I get the postion from a servo.
Thank you Coleman
Could you provide me the information of manufactory ----------- phone number or E-mail address, to get the answer of
What is the maximum force (load) at the axial direction and radial direction of a hitec servo like RB-Hit-30 ?
Hi jack_lai,
Welcome to the RobotShop Forum. There is actually a lot of information on the web about how a servo motor works, so we won’t go into too much detail here. Simply put, a microcontroller / servo controller sends a timed pulse of between 500us and 2500us which corrresponds to 0 degrees and “max” degrees (usually 180). The eletronics within the servo take that timed input and rotate the servo to the corresponding position. The timed pulse needs to be repeated at least every 30ms for the servo to keep its position. If you try to rotate the shaft, the motor will try to return it to the desired location, requiring current. If there is no load (torque) acting against the shaft, it requires only minimal current to keep its location. The torque rating (4.1Kg-cm) would be able to provide that torque when rotating or keeping a position.
Hope this helps,
Glad to help,
A servo motor requires a timed pulse between 500us and 2500us at 5V. Usually this is connected to a digital pin. The signal you send to a servo is very different than the signal you send to a servo controller.
Usually, yes. Some single board computers have USB connections, and some microcontrollers may also have USB connection.
Most servos are not directly programmable, so you need a microcontroller or servo motor controller to send them position signals. To program the microcontroller or servo controller, you usually need a computer, and a USB port is certainly helpful. If the microcontroller does not directly have a USB port, you will need a serial to USB adapter. Some servo controllers have knobs which allow you to manually move the servos.
Hope this helps,
Hi,
1.15 sec/60 degrees means it takes 1.15 seconds to rotate 60 degrees. Most servos cannot rotate more than 180 degrees, which is why the time to rotate 60 degrees is more important than an “RPM” (since it cannot do complete revolutions).
Therefore it takes 6 * 1.15 = 6.9 seconds per 360 degrees, or in other words, 6.9 seconds per revolution.
Therefore in 1 minute (60 seconds), it would be the equivalent of turning at (60/1.15)*60 = 3130 degrees.
Since there are 360 degrees in a revolution, 3130 / 360 = 8.69 revolutions per minute.
Hope this helps,
Hi jack_lai,
We offer a variety of books which would teach you the basics of building robots, including Robot Builder’s Bonanza, Robot Building for Dummies, Robots, Androids and Animatronics and more. We offer a complete C# 4.0 reference manual, though many concepts are not used specifically in robotics. You may want to start with something simple like Arduino (based on C).
Hope this helps,
Hi Jack,
With several hundred microcontrollers in these categories, we are not in a position to list every microcontroller which can be programmed in C. Basic Atom, Basic X and NanoCore are programmed in BASIC. Parallax and PicAxe are programmed in versions of BASIC. Arduino and Pololu are programmable in C. There are many different microcontrollers under “32-bit microcontrollers” and “miscellaneous” so it’s better to look at it on a case by case basis.
Sincerely,
Hi,
Q1.What is meaning “standard size” Hitec servos
A1. Servos can be made in all shapes and sizes. A “standard sized” servo has similar dimensions to the HS422 from Hitec. There are many third party parts made fof this type of servo.
Q2.If I buy a “SPT400 Gear Drive Tilt System (5:1)” robotshop.ca/servocity-sp…box-5-1-4.html
Could I mount “HS-805BB Giant Scale Servo Motor” on it ? robotshop.ca/hitec-hs805BB-servo-motor.html
A2 No - the 805BB is physically too large to fit in the opening.
Q3. could I change the gear in “HS-805BB Giant Scale Servo Motor” in order to get more torque ?
A3. No - the motor inside the servo and the gear ratio determines the torque the servo can output. Hitec offers metal gears which decrease the chance of a gear breaking, but does not change the motor or the gear ratio.
Q4.Stall current is meanning “load current” ?
“HS-785HB Winch Servo Motor” 's stall current is 1500 mA at 4.8 V robotshop.ca/PDF/HS-785HB.pdf
“HS-805BB Giant Scale Servo Motor” 's stall current I can not find at robotshop.ca/hitec-hs805BB-servo-motor.html
I guess it is more than 5000 mA.
My device maybe runs at least 2x HS-785HB Winch Servo Motor"s and 2x HS-805BB Giant Scale Servo Motor"s. and I need control the speed and the direction (clockwise and count-clockwise). if I use “Arduino Uno USB Microcontroller”
What motor drivor I should choose ?
A4. When a servo has been sent to a specific angle, it will try its very best to stay there and resist changes. This means that it will be operating close to its loaded / stall current. The 805BB stall will certainly be higher than 1.5A. We can get the value if you are still interested. You can use almost any standard servo motor controller, except if the current is very high, check the schematic to see if the servos are being powered directly by the batteries or by the microcontroller.
Q5. what power supplyer I should choose ? could I use the power box of PC computer. It has 5V DC with big current.
A5. You can use the 5V output from a computer power supply for high current applications.
Hope this helps,
Hi Jack,
It is important to keep all relevant threads together in one post (rather than create a new thread each time, please just reply to the last post in this thread if you are talking about the same subject). A servo uses a potentiometer which cannot do continuous rotation. When modifying a sevo for continuous rotation, you normally need to remove the potentiometer (and therefore no longerhave position feedback). If you still want position feedback, you will need to either connect an encoder (there are currently no encoders made for servos) or use an external continuous rotation potentiometer (which we do not offer).
Hope this helps,