Feeling Their Way Around: Robot Sensors

Humans are capa­ble of sens­ing envi­ron­men­tal fac­tors around them and are aware of what each of their body parts is doing at any giv­en time, while robots are not afford­ed this lux­u­ry. Small, light­weight sen­sors help the robots adjust to where they are, what they are doing, and where their own parts are. Engi­neers increase the num­ber of sen­sors used on a robot as the robot gets more com­plex. A sin­gle task may require a com­bi­na­tion of dif­fer­ent sensors.

Light sen­sors detect light and cre­ate a volt­age dif­fer­ence. Pho­tore­sis­tor and pho­to­volta­ic cells are the most com­mon types of light sen­sors. Photoresistor’s resis­tance varies with change in light inten­si­ty and are eas­i­ly imple­ment­ed. Pho­to­volta­ic cells con­vert solar radi­a­tion into elec­tri­cal energy.

Sound sen­sors detect sound and return a volt­age pro­por­tion­al to the sound lev­el. The sen­sor is usu­al­ly a micro­phone, and can help even a sim­ple robot nav­i­gate based on the sound it receives. Com­plex robots can use a micro­phone for speech and voice recognition.

A push but­ton switch, lim­it switch, and tac­tile bumper are exam­ples of con­tact sen­sors. They are typ­i­cal­ly used for robots to avoid obsta­cles, and are trig­gered when phys­i­cal con­tact against oth­er objects is estab­lished. After an object is bumped, the sen­sor trig­gers the robot to reverse, turn, stop, etc. Touch screen smart phones and oth­er devices use a form of a con­tact sensor.

Instead of allow­ing the robot to make phys­i­cal con­tact with an obsta­cle, a prox­im­i­ty sen­sor can be installed so that the robot can detect the pres­ence of a near­by object with­in a giv­en dis­tance. A trans­mit­ter sends elec­tro­mag­net­ic radi­a­tion or elec­tro­sta­t­ic field, and the receiv­er ana­lyzes the return sig­nal for inter­rup­tions. Exam­ples of prox­im­i­ty sen­sors are infrared trans­ceivers, ultra­son­ic sen­sors, and photoresistors.

Indus­tri­al man­u­fac­tur­ers ben­e­fit from pres­sure sen­sors. Tac­tile pres­sure sen­sors are sen­si­tive to touch, force, and pres­sure. If the robot hand needs to apply a cer­tain amount of grip and pres­sure required to hold an object, the pres­sure sen­sor is the solution.

Posi­tion­ing sen­sors approx­i­mate the posi­tion of the robot; GPS is the most com­mon­ly used. Satel­lites trans­mit sig­nals and a receiv­er on the robot acquires these sig­nals to process. GPS sys­tems are ben­e­fi­cial for out­door robots. Dig­i­tal mag­net­ic com­pass and local­iza­tion are oth­er posi­tion­ing sensors.

When robots are required to work in extreme envi­ron­ments, a tem­per­a­ture sen­sor might be nec­es­sary. Tem­per­a­ture sen­sor ICs pro­vide volt­age dif­fer­ence for a change in temperature.

Robots​.com can help you incor­po­rate an indus­tri­al robot with robot­ic sen­sors. Con­tact us today on how to pick the right sen­sors for your facil­i­ty; online or at 877−762−6881.