"Current-based" cadence-sensing from Ride1up

[Explorer-1]

Just go to throttle, and forget all the damn sensors.

... but then it not really cycling is it? A great way to solve the problem, that's what i have to do on my 'scooter' bike, it was never made for pedaling anyway so no point it getting frustrated with it. I consider it a poor design for the bike, but the 100 mile range is an awesome design, so I can live with the limitations.

 

[PSm]

Trying to understand the advanced "current-based" (CB) cadence-sensing assist now offered on some Ride1Up models. Follow the link for their description.

Sounds like CB assist doles out power as a function of motor current, up to a fraction of max motor power set by assist level. Ride1Up claims that motor current can be tied somehow to "desired exertion" without measuring rider torque.

Question: Anyone know of an exploitable connection between desired exertion and motor current?

Can’t comment on the marketing speak, but all I can say is that my Ride1UP CF Racer1 implementation is really smooth and efficient. Feels a lot like my traditional road bike, and with different assist levels just feels like a tailwind of different levels. Can get a lot of range, riding with motor off or lower assist levels, and higher levels rarely needed (since I like to ride e-bikes more like a regular bike)

 

[Jeremy McCreary]

Can’t comment on the marketing speak, but all I can say is that my Ride1UP CF Racer1 implementation is really smooth and efficient. Feels a lot like my traditional road bike, and with different assist levels just feels like a tailwind of different levels. Can get a lot of range, riding with motor off or lower assist levels, and higher levels rarely needed (since I like to ride e-bikes more like a regular bike)

Your bike definitely uses the current-based assist per Ride1Up. Glad to hear how well it works.

Still trying to understand the "current-based" part, though. Your description of the riding experience prompted me to reread Ride1Up's blurb:

Our R1CBC systems operate on a current-based rather than speed-based programming. This means the PAS level changes the amount of current or wattage the motor provides, offering assistance based on your desired effort level, not your speed. This feature allows for a more natural and seamless riding experience compared to traditional speed-based systems, which can feel unresponsive, abrupt, and unnatural.

Maybe assist level sets a motor current level rather than max assisted speed. The cadence sensor still functions as an on-off switch for the motor, but when the motor's on, it can only draw the selected current from the controller.

At constant input voltage, motor current correlates directly with output torque and indirectly with mechanical power output.

Does that sound plausible to you?

 

[OrTrek]

Jeremy, I think you and PSm are located within the same area. Why not just see if the two of you could meet up and then you ride his CF Racer? Also there is a "explanation" of their cadence based systems on their site and also I remember a podcast about it (don't remember where). They do use a sine wave controller as opposed to a square wave. I find my Roadsters pretty natural - much like PSm gets with his Racer. And I ride the this light single speed w/o assist or in level 1, 95% of the time.

 

[Jeremy McCreary]

Jeremy, I think you and PSm are located within the same area. Why not just see if the two of you could meet up and then you ride his CF Racer? Also there is a "explanation" of their cadence based systems on their site and also I remember a podcast about it (don't remember where). They do use a sine wave controller as opposed to a square wave. I find my Roadsters pretty natural - much like PSm gets with his Racer. And I ride the this light single speed w/o assist or in level 1, 95% of the time.

I'd love to see how this approach actually rides, but that probably won't answer my still-unanswered question. Out of an engineering interest in ebike power control, I've read everything Ride1Up has to say about current-based cadence-sensing assist and still don't know where current comes in. Neither does anyone else writing about it.

The ebiking world would be a better place with an assist option that's less expensive than torque-sensing but more sophisticated than the typical all-or-nothing assist on most cadence-sensing ebikes.

Judging from your riding experience and @PSm 's, this current-based cadence-sensing from Ride1Up could well be that option. I think that's something to be curious about.

 

[Mango1234]

I have a Ride1Up 500 Series bike. What they are describing is not new. The PAS levels and are programmable, so I chose 7 levels that I set at 10%, 15, 22, 33,50,75, and 100%. When on the 100% PAS level the wattage display goes up to 1040W with a fully charged battery and 900something watts on a low battery. The PAS level is current based because the wattage falls as the voltage does. I don't think you get full power when your cadence is too low just like my other, older ebike. This is a bunch of marketing fluff to describe a system that has been around since at least 2021. I don't think it is some super special new invention, but it is good, I bought one and like it.

 

[PCeBiker]

The PAS levels and are programmable, so I chose 7 levels that I set at 10%, 15, 22, 33,50,75, and 100%.

I Like That !!
My "PAS" levels are kind of adjustable, but not programmable.

I adjusted my first "Throttle Gear" to 20%, but I have no idea what % the other gears are at?

Here's what the manual has to say about it,..


ELECTRIC BICYCLE METER KT—LCD8H Product User Manual

When C4 = 4 is confirmed, the "percentage value of the first gear speed accounts for its full speed" of the power assist gear flashes, press (UP) button or (DOWN) button for short to make selection, and the default value is 50%. The percentage values of other gears divide automatically in equal.



I have no idea what the hell they're talking about.

 

[Mango1234]

I meant to say the number of PAS levels and their percents are programmable. You can choose 3,5,7, or 9 levels. Each level is programmable 1-100% if I recall.

 

[PCeBiker]

I meant to say the number of PAS levels and their percents are programmable. You can choose 3,5,7, or 9 levels. Each level is programmable 1-100% if I recall.

My KT controller has normal speed based PAS modes, but you can switch it to what they call "Imitation torque control" which is just current based control with "Throttle Gears" instead.

I'm sure it's the same as your PAS modes.

Each of my throttle gears has a maximum current and speed. I get to that speed using the allotted 20% power for first gear.
Second throttle gear gives me maybe 35%? (other gears divide automatically in equal.) and a bit more speed as well.
5th gear gives me the full 25amps and 34.2 kph with a fully charged battery.
Once I get to maximum speed in any gear, the power drops off to maintain the maximum speed for that gear.

 

[PCeBiker]

I have a Ride1Up 500 Series bike.

I'm just curious, can you make all those adjustments with your display, or do you need a computer and a patch cord and three years of programming experience?

 

[mclewis1]

I've been watching this thread and getting a good chuckle out of many of the comments as well as Ride1Up's marketing statements.

The idea that a power (wattage/amps whatever) based cadence sensed PAS setup is somehow new is a bit humorous. This has been the default how a Grin Cycle Analyst (CA) has implemented PAS control for many many years. In addition to limiting the wattage to the motor for each PAS level selected the CA also ramps the power so the cadence sensor doesn't feel just like an ON/OFF switch. The CA also works in much the same way when the input is a torque sensor.

This capability is the default how a CA comes these days (and has for quite a while, at least AFAIK as long as the RtR or Ready to Run kits have been offered), and doesn't despite PCeBiker's suggestion require any cords or programming experience (at least I think this is what is being referred to).

While not quite as smooth, "natural", or graduated as a torque sensor's input, the CA's management of the cadence input provides a riding experience that is somewhere in between the poor PAS implementations that are so prevalent and a full on torque sensor setup. This makes a cadence PAS a simple, inexpensive (vs a BB torque sensor) setup offering a very bicycle like riding experience. I've never understood why more ebike controllers haven't offered the power rather than speed based programming.

So not only is it possible, it's been done for years and years and is nothing new at all.

Really interesting IMHO beyond the CA managing a torque sensor input in much the same way as it handles the cadence based PAS is the addition of regen braking (hub motor dependent) based on the rotation of the crank (pedalling backwards) to initiate progressive braking much like a coaster brake setup. I can see this idea used on a really simple cruiser/around town style bike with very minimal ebike characteristics (integrated batteries, no or very limited display, torque sensing, internal wiring, no external add on sensors and a small diameter hub motor) and perhaps only a front brake lever. To me that would be something new and interesting.

 

[Jeremy McCreary]

I appreciate all the info, but the original question isn't about when current-based cadence-sensing (CBCS) came on the scene, or who invented it, or how KT and Grin implement their cadence-sensing assist, or even how programmable Ride1Up's system is.

It's a technical question about how Ride1Up uses CURRENT in its CBCS. Most of the replies here don't even mention current.

I don't dismiss Ride1Up's claim about using current to control assist as pure marketing mumbo-jumbo. Some experienced riders have reported riding experiences quite different from basic cadence-sensing assist, so Ride1Up's clearly doing something different under the hood. And I want to know what it is.

We have a clue: It involves motor current. Let's ponder how that might result in the user-reported riding experiences without directly measuring either torque or RPM at the crank.

 

[rcdanner]

I have Aventon Pace 500.2 with speed based cadence. It 'rides' to a set speed based on your PAS level setting. For instance, Level 2 gets me about 15-16mph with normal pedal effort. Maybe a1 mph higher with strong pedal effort. Going up hill at Level 2 my speed hardly drops (if any) with normal pedal effort. But the controller increases power to the motor dramatically.
I also have an older Ride1Up LMTD with power based cadence. It rides to a set power level based on your PAS level setting. For instance, Level 2 outputs about 250watts to the motor no matter how much pedal effort. Your speed will vary. Go uphill and your speed will drop as you pedal at the same effort as before the hill. Pedal harder and you will go a little faster. But the motor power will remain around 250 watts. Power levels are programmable in the display.
I really like the Ride1Up cadence system. It isn't as smooth as torque. There is the cadence 'on-off' power thingy. But it feels so much more natural bike riding experience than Speed Based Cadence. And I can predict my riding range much better knowing the constant power output versus a constantly changing power output of speed based cadence systems.

 

[Gionnirocket]

I appreciate all the info, but the original question isn't about when current-based cadence-sensing (CBCS) came on the scene, or who invented it, or how KT and Grin implement their cadence-sensing assist, or even how programmable Ride1Up's system is.

It's a technical question about how Ride1Up uses CURRENT in its CBCS. Most of the replies here don't even mention current.

I don't dismiss Ride1Up's claim about using current to control assist as pure marketing mumbo-jumbo. Some experienced riders have reported riding experiences quite different from basic cadence-sensing assist, so Ride1Up's clearly doing something different under the hood. And I want to know what it is.

We have a clue: It involves motor current. Let's ponder how that might result in the user-reported riding experiences without directly measuring either torque or RPM at the crank.

Dude... Go for a ride already!

 

[Jeremy McCreary]

I also have an older Ride1Up LMTD with power based cadence. It rides to a set power level based on your PAS level setting. For instance, Level 2 outputs about 250watts to the motor no matter how much pedal effort. Your speed will vary. Go uphill and your speed will drop as you pedal at the same effort as before the hill. Pedal harder and you will go a little faster. But the motor power will remain around 250 watts. Power levels are programmable in the display.
I really like the Ride1Up cadence system. It isn't as smooth as torque. There is the cadence 'on-off' power thingy. But it feels so much more natural bike riding experience than Speed Based Cadence.

This is a very helpful data point. Your display's power reading is for electrical power to the motor. Assuming fixed input voltage, if assist level ultimately sets a fixed motor current in Ride1Up's current-based assist, it would show as a fixed power reading on your display. There would be little or no variation with torque or RPM at the crank, or with wheel speed.

I'm sure the implementation isn't as simple as that in detail. But it's a plausible heuristic.

 

[Mango1234]

I just went on a very windy ride. My Ride1Up 500 does give full power at any cadence. There is no speed limit per PAS level, only a global limit which is fixed at 45kph on PAS. The throttle speed limit is adjustable. It does have a couple of seconds acceleration ramp after the cranks turn a bit. There is a setting called 'sensitivity' that I think changes how far the cranks have to turn before the motor starts. All settings are easily accessible on the display.

 

[BlackHand]

This is a very helpful data point. Your display's power reading is for electrical power to the motor. Assuming fixed input voltage, if assist level ultimately sets a fixed motor current in Ride1Up's current-based assist, it would show as a fixed power reading on your display. There would be little or no variation with torque or RPM at the crank, or with wheel speed.

I'm sure the implementation isn't as simple as that in detail. But it's a plausible heuristic.

Which is pretty much what several people have already described in this thread. I think you're getting caught up in the semantics a bit. Maybe you're taking the term 'current based' literally? Think current limited vs speed limited instead - more descriptive of how they function but would never get past marketing. Hence current based and speed based.

No one here wrote the programming for R1U's controller, so you're only going to get high level answers which will pretty much apply to all current based systems regardless of brand. Sure, there are probably some differences in power ramp-up/roll-off and sampling rate but ultimately assist levels are set by the controller limiting the power drawn through it by the motor.

 

[Jeremy McCreary]

Which is pretty much what several people have already described in this thread. I think you're getting caught up in the semantics a bit. Maybe you're taking the term 'current based' literally? Think current limited vs speed limited instead - more descriptive of how they function but would never get past marketing. Hence current based and speed based.

No one here wrote the programming for R1U's controller, so you're only going to get high level answers which will pretty much apply to all current based systems regardless of brand. Sure, there are probably some differences in power ramp-up/roll-off and sampling rate but ultimately assist levels are set by the controller limiting the power drawn through it by the motor.

Yes, I'm taking "current-based" literally for now cuz it's all we have to go on.

I've read every post here at least twice, and no one described the riding experience as clearly and objectively as @rcdanner . But still no mention of current, just power. And they are by no means the same thing from an engineering standpoint.

Agree, no one here wrote the Ride1Up controller code, but we have members who know a lot about ebike technology. Not unreasonable to imagine that someone might have some insight into how a cadence sensor and motor current could be combined to provide a better riding experience than with the usual all-or-nothing cadence-sensing assist.

That's all I want to know. Curiosity is a good thing.

 

[Gionnirocket]

Curiosity dead ends at testa dura